[go: up one dir, main page]

WO2009122990A1 - Elément à effet magnétorésistif et mémoire magnétique à accès aléatoire - Google Patents

Elément à effet magnétorésistif et mémoire magnétique à accès aléatoire Download PDF

Info

Publication number
WO2009122990A1
WO2009122990A1 PCT/JP2009/056044 JP2009056044W WO2009122990A1 WO 2009122990 A1 WO2009122990 A1 WO 2009122990A1 JP 2009056044 W JP2009056044 W JP 2009056044W WO 2009122990 A1 WO2009122990 A1 WO 2009122990A1
Authority
WO
WIPO (PCT)
Prior art keywords
magnetization
ferromagnetic layer
layer
fixed region
magnetization fixed
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2009/056044
Other languages
English (en)
Japanese (ja)
Inventor
俊輔 深見
延行 石綿
哲広 鈴木
則和 大嶋
聖万 永原
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NEC Corp filed Critical NEC Corp
Priority to JP2010505748A priority Critical patent/JP5445970B2/ja
Publication of WO2009122990A1 publication Critical patent/WO2009122990A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11C—STATIC STORES
    • G11C11/00—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor
    • G11C11/02—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements
    • G11C11/16—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements using elements in which the storage effect is based on magnetic spin effect
    • G11C11/165—Auxiliary circuits
    • G11C11/1653—Address circuits or decoders
    • G11C11/1655—Bit-line or column circuits
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11C—STATIC STORES
    • G11C11/00—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor
    • G11C11/02—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements
    • G11C11/16—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements using elements in which the storage effect is based on magnetic spin effect
    • G11C11/161—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements using elements in which the storage effect is based on magnetic spin effect details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11C—STATIC STORES
    • G11C11/00—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor
    • G11C11/02—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements
    • G11C11/16—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements using elements in which the storage effect is based on magnetic spin effect
    • G11C11/165—Auxiliary circuits
    • G11C11/1659—Cell access
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11C—STATIC STORES
    • G11C11/00—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor
    • G11C11/02—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements
    • G11C11/16—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements using elements in which the storage effect is based on magnetic spin effect
    • G11C11/165—Auxiliary circuits
    • G11C11/1675—Writing or programming circuits or methods
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10B—ELECTRONIC MEMORY DEVICES
    • H10B61/00—Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices
    • H10B61/20—Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices comprising components having three or more electrodes, e.g. transistors
    • H10B61/22—Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices comprising components having three or more electrodes, e.g. transistors of the field-effect transistor [FET] type
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N50/00—Galvanomagnetic devices
    • H10N50/10—Magnetoresistive devices

Definitions

  • the present invention relates to a magnetoresistive effect element and a magnetic random access memory.
  • the present invention relates to a domain wall motion type magnetoresistive effect element and a magnetic random access memory.
  • Magnetic random access memory (Magnetic Random Access Memory; MRAM) is expected to be a non-volatile memory capable of high-speed operation and infinite rewriting, and has been actively developed.
  • MRAM Magnetic Random Access Memory
  • a magnetic material is used as a storage element, and information is stored in correspondence with the magnetization direction of the magnetic material.
  • Several methods have been proposed as a method for switching the magnetization of the magnetic material, but all of them are common in that current is used. For practical use of MRAM, it is very important how much the write current can be reduced. According to Non-Patent Document 1 below, the write current can be reduced to 0.5 mA or less, more preferably 0.2 mA or less. Reduction is required.
  • Non-Patent Document 1 Sakimura, N. et al., “MRAM Cell Technology for Over 500-MHz SoC, ”April 2007, IEEE Journal of Solid State Circuits, Vol. 42, Issue 4, p830-838
  • the most common method of writing information to the MRAM is to arrange a wiring for writing around the magnetic memory element, and to change the magnetization direction of the magnetic memory element by a magnetic field generated by passing a current through the wiring. It is a method of switching. Since this method uses magnetization reversal by a magnetic field, writing in 1 nanosecond or less is possible in principle, which is preferable for realizing a high-speed MRAM.
  • the magnetic field for switching the magnetization of the magnetic material that has ensured thermal stability and disturbance magnetic field resistance is generally about several tens of Oe (Yersted), and in order to generate such a magnetic field, about several mA. A current is required.
  • the chip area is inevitably increased, and the power consumption required for writing increases, so that it is inferior in competitiveness compared to other random access memories.
  • the write current further increases, which is not preferable in terms of scaling.
  • the first is spin injection magnetization reversal.
  • a laminated film composed of a first magnetic layer having reversible magnetization and a second magnetic layer electrically connected to and fixed in magnetization is formed.
  • the first magnetic layer is used.
  • Information is recorded by reversing the magnetization of the magnetic layer. Since spin injection magnetization reversal occurs at a certain current density or higher, the current required for writing is reduced as the element size is reduced.
  • the spin injection magnetization reversal method is excellent in scaling.
  • an insulating layer is provided between the first magnetic layer and the second magnetic layer, and a relatively large current must be passed through the insulating layer at the time of writing. Sex is an issue.
  • the current path for writing and the current path for reading are the same, there is a concern about erroneous writing during reading.
  • spin transfer magnetization reversal is excellent in scaling, there are some barriers to practical use.
  • Patent Document 1 Japanese Patent Application Laid-Open No. 2005-191032
  • an MRAM using a current-induced domain wall motion phenomenon is generally antiparallel to the first magnetic layer having reversible magnetization. It is fixed to become. In such a magnetization arrangement, a domain wall is introduced into the first magnetic layer.
  • Non-Patent Document 2 when a current is passed in the direction penetrating the domain wall, the domain wall moves in the direction of the conduction electrons, so that a current is passed through the first magnetic layer. Writing becomes possible.
  • Non-Patent Document 2 Yamaguchi, A. et al., “Real-Space Observation of Current-Driven Domain Wall Motion in Submicron Magnetic Wires, ”Physical Review Letters, Vol. 92, February 2004, number 7, p77205
  • Non-Patent Document 2 the current density required for current-induced domain wall movement requires about 1 ⁇ 10 8 [A / cm 2 ]. In this case, for example, when the width of the layer in which the domain wall motion occurs is 100 nm and the film thickness is 10 nm, the write current is 1 mA. This cannot satisfy the above-mentioned conditions concerning the write current. However, the following Non-Patent Document 3 reports that the write current can be reduced sufficiently by using a material having perpendicular magnetic anisotropy as a ferromagnetic layer in which current-induced domain wall motion occurs.
  • Non-Patent Document 3 Fukami, S. et al., “Micromagnetic analysis of current driven domain wall motion in nano-strips with perpendicular magnetic anisotropy, ”52nd Annual Conference on Magnetism and Magnetic Materials, Abstracts, January 2007, p352
  • Non-Patent Document 4 observation of current-induced domain wall motion in a perpendicular magnetic film is reported.
  • Non-Patent Document 4 Tanigawa, H. et al., “Current-Driven Domain Wall Motion in CoCrPt Wires with Perpendicular Magnetic Anisotropy ”, Applied Physics Express, Vol. 1, No. 1, January 11, 2008, p011301
  • Non-Patent Document 4 a domain wall is introduced by providing a step in a layer where domain wall movement occurs. is doing.
  • domain wall introduction that is, initialization method used in Non-Patent Document 4
  • regions having different magnetic characteristics are formed by providing a step in the perpendicular magnetization film, and the difference in coercivity between these regions is utilized.
  • Domain walls are introduced by applying an external magnetic field in multiple steps.
  • such a method is not only complicated, but also requires a sufficient margin for the magnetic field into which the domain wall is introduced, and is not suitable for manufacturing a large-scale memory system.
  • a large magnetic field is applied to the domain wall introduced near the step in the direction parallel to the film surface. There is a concern that the pinning force of the domain wall becomes excessive due to this magnetic field. This is not preferable from the viewpoint of reducing the write current.
  • a first object of the present invention is to provide a magnetic random access memory capable of introducing a domain wall by a simple and easy method.
  • a second object of the present invention is to provide a magnetic random access memory capable of writing at a low current density by appropriately adjusting the pinning force of the domain wall.
  • a magnetic random access memory according to one aspect of the present invention will be described.
  • a magnetic random access memory according to one aspect of the present invention has a plurality of magnetic memory cells arranged in an array, and each magnetic memory cell has a magnetoresistive effect element.
  • the magnetoresistance effect element includes at least a first ferromagnetic layer and a second ferromagnetic layer group.
  • the first ferromagnetic layer includes at least a first magnetization fixed region, a second magnetization fixed region, and a magnetization free region, and the first magnetization fixed region and the second magnetization fixed region are provided connected to the magnetization free region.
  • the second ferromagnetic layer group includes a second ferromagnetic layer and a coupling layer. The second ferromagnetic layer and the coupling layer are adjacent to each other. The second ferromagnetic layer group is magnetically coupled to the first magnetization fixed region.
  • the first ferromagnetic layer and the second ferromagnetic layer group have at least a portion of a ferromagnetic material having perpendicular magnetic anisotropy.
  • the first magnetization fixed region and the second magnetization fixed region have magnetizations fixed in antiparallel directions to each other at least in part.
  • the magnetization free region has reversible magnetization at least at a part, and faces a direction parallel to either the first magnetization fixed region or the second magnetization fixed region. In such a magnetization arrangement, a domain wall is introduced into the first ferromagnetic layer group.
  • the second ferromagnetic layer group includes the second ferromagnetic layer and is magnetically coupled to the first magnetization fixed region. Furthermore, in the second ferromagnetic layer group, at least a part of the second ferromagnetic layer group has a magnetization fixed in an antiparallel direction to the magnetization of the first magnetization fixed region. In order to realize such magnetization in the antiparallel direction (Ferri coupling), the coupling layer magnetically couples the first magnetization fixed region and the second ferromagnetic layer in the antiparallel direction.
  • a further ferromagnetic layer, nonmagnetic layer, conductive layer, and the like are appropriately provided.
  • at least one ferromagnetic layer and at least one nonmagnetic layer are provided.
  • An external magnetic field is used as a method for initializing the memory state of the magnetoresistive effect element according to one aspect of the present invention.
  • a sufficiently large external magnetic field is applied to the magnetoresistive element in the direction perpendicular to the film surface, the magnetization free region, the second magnetization fixed region, and the second ferromagnetic layer face the direction of the external magnetic field, and the second ferromagnetic layer And the first magnetization fixed region that is ferrimagnetically coupled to face the opposite direction to the external magnetic field.
  • a domain wall is introduced at the boundary between the first magnetization fixed region and the magnetization free region.
  • a current induced domain wall motion phenomenon is used as a method for writing information to the magnetoresistive effect element according to one aspect of the present invention.
  • the magnetoresistive effect is used as a method for reading information from the magnetoresistive effect element according to one aspect of the present invention.
  • the memory state can be initialized by applying an external magnetic field once. Further, depending on the magnetic characteristics of the second magnetization fixed region and the second ferromagnetic layer, a two-step external magnetic field application step is required. In this case, a sufficiently large initialization margin can be obtained. That is, a domain wall can be introduced by a simple initialization process, and a large initialization magnetic field margin can be easily secured.
  • the write current can be reduced in the perpendicular magnetic domain wall motion type MRAM. This is because the influence of the magnetic field on the pin site of the domain wall can be adjusted by appropriately designing the leakage magnetic field in the step region to the configuration of the second ferromagnetic layer group (20).
  • FIG. 1A is a perspective view showing the structure of the main part of a magnetoresistive effect element according to one embodiment of the present invention.
  • FIG. 1B is a plan view showing the structure of the main part of the magnetoresistive effect element according to one embodiment of the present invention.
  • FIG. 1C is a cross-sectional view showing the structure of the main part of the magnetoresistive effect element according to one embodiment of the present invention.
  • FIG. 2 is a cross-sectional view showing an example of the magnetization structure of the magnetoresistive effect element according to one embodiment of the present invention.
  • FIG. 3A is a schematic diagram for explaining the principle of the initialization method used in the embodiment of the present invention.
  • FIG. 3B is a schematic diagram for explaining the principle of the initialization method used in the embodiment of the present invention.
  • FIG. 4A is a magnetization curve of a laminated film obtained by laminated ferrimagnetic coupling.
  • FIG. 4B is a magnetization curve of a laminated film formed by laminated ferrimagnetic coupling.
  • FIG. 4C is a magnetization curve of a laminated film formed by laminated ferrimagnetic coupling.
  • FIG. 5 is a cross-sectional view for explaining a method of initializing the memory state of the magnetoresistive effect element according to one embodiment of the present invention.
  • FIG. 5 is a cross-sectional view for explaining a method of initializing the memory state of the magnetoresistive effect element according to one embodiment of the present invention.
  • FIG. 6A is a cross-sectional view for explaining another method of initializing the memory state of the magnetoresistive effect element according to one embodiment of the present invention.
  • FIG. 6B is a cross-sectional view for explaining another method of initializing the memory state of the magnetoresistive effect element according to the exemplary embodiment of the present invention.
  • FIG. 7A is a cross-sectional view for explaining a method of writing information to the magnetoresistive element according to one embodiment of the present invention.
  • FIG. 7B is a cross-sectional view for explaining a method of writing information to the magnetoresistive element according to one embodiment of the present invention.
  • FIG. 8A is a cross-sectional view for explaining a method of reading information from the magnetoresistive effect element according to one embodiment of the present invention.
  • FIG. 8A is a cross-sectional view for explaining a method of reading information from the magnetoresistive effect element according to one embodiment of the present invention.
  • FIG. 8B is a cross-sectional view for explaining a method of reading information from the magnetoresistive effect element according to one embodiment of the present invention.
  • FIG. 9 is an example of a circuit diagram for one cell of the magnetic memory cell according to one embodiment of the present invention.
  • FIG. 10A is a perspective view showing the structure of the main part of the first modification of the magnetoresistance effect element according to the present invention.
  • FIG. 10B is a cross-sectional view showing the structure of the main part of the first modification of the magnetoresistance effect element according to the present invention.
  • FIG. 10C is a cross-sectional view showing the structure of the main part of the first modification of the magnetoresistance effect element according to the present invention.
  • FIG. 10A is a perspective view showing the structure of the main part of the first modification of the magnetoresistance effect element according to the present invention.
  • FIG. 10B is a cross-sectional view showing the structure of the main part of the first modification of the magnetoresistance effect element according to the present
  • FIG. 11A is a cross-sectional view showing the structure of the main part of a second modification of the magnetoresistive effect element according to the present invention.
  • FIG. 11B is a schematic diagram for explaining the operation of the second modification of the magnetoresistance effect element according to the present invention.
  • FIG. 11C is a schematic diagram for explaining the operation of the second modification of the magnetoresistance effect element according to the present invention.
  • FIG. 12 is a cross-sectional view showing the structure of the main part of another second modification of the magnetoresistive effect element according to the present invention.
  • FIG. 13 is a sectional view showing the structure of the main part of still another second modified example of the magnetoresistive effect element according to the present invention.
  • FIG. 14A is a perspective view showing the structure of the main part of the third modification of the magnetoresistance effect element according to the present invention.
  • FIG. 14B is a plan view showing the structure of the main part of the third modification of the magnetoresistance effect element according to the present invention.
  • FIG. 15 is a cross-sectional view showing the structure of the main part of the third modification of the magnetoresistive effect element according to the present invention.
  • FIG. 16 is a cross-sectional view showing the structure of the main part of another third modification of the magnetoresistance effect element according to the present invention.
  • FIG. 17 is a cross-sectional view showing the structure of the main part of still another third modification of the magnetoresistance effect element according to the present invention.
  • FIG. 18A is a perspective view showing the structure of the main part of a fourth modification of the magnetoresistance effect element according to the present invention.
  • FIG. 18B is a plan view showing the structure of the main part of the fourth modification example of the magnetoresistance effect element according to the present invention.
  • FIG. 18C is a cross-sectional view showing the structure of the main part of a fourth modification of the magnetoresistance effect element according to the present invention.
  • FIG. 19A is a cross-sectional view for explaining a method of reading information in the fourth modified example.
  • FIG. 19B is a cross-sectional view for explaining the information reading method in the fourth modified example.
  • FIG. 20A is a plan view showing the structure of the main part of the fifth modification example of the magnetoresistance effect element according to the present invention.
  • FIG. 20B is a plan view showing the structure of the main part of the fifth modification example of the magnetoresistance effect element according to the present invention.
  • FIG. 21A is a plan view showing the structure of the main part of another fifth modification of the magnetoresistance effect element according to the present invention.
  • FIG. 21B is a plan view showing the structure of the main part of another fifth modification of the magnetoresistance effect element according to the present invention.
  • FIG. 22A is a plan view showing a structure of a main part of still another fifth modification example of the magnetoresistance effect element according to the present invention.
  • FIG. 22B is a plan view showing the structure of the main part of still another fifth modification example of the magnetoresistance effect element according to the present invention.
  • FIG. 23A is a plan view for explaining the information writing method in the fifth modification shown in FIGS. 22A and 22B.
  • FIG. 23B is a plan view for explaining the information writing method in the fifth modification shown in FIGS. 22A and 22B.
  • the magnetic random access memory according to the present embodiment has a plurality of magnetic memory cells arranged in an array, and each magnetic memory cell has a magnetoresistive effect element.
  • FIGS. 1B and 1C schematically show an example of an embodiment of a main part of a magnetoresistive effect element according to the present invention.
  • 1A is a perspective view
  • FIGS. 1B and 1C are an xy plan view and an xz sectional view in the xyz coordinate system shown in FIG. 1A.
  • the magnetoresistive effect element includes at least a first ferromagnetic layer 10 and a second ferromagnetic layer group 20.
  • the first ferromagnetic layer 10 includes at least a first magnetization fixed region 11a, a second magnetization fixed region 11b, and a magnetization free region 12.
  • the first magnetization fixed region 11 a and the second magnetization fixed region 11 b are provided in connection with the magnetization free region 12.
  • 1A, 1B, and 1C a first magnetization fixed region 11a is provided connected to one end of the magnetization free region 12, and a second magnetization fixed region 11b is provided connected to the other end.
  • the second ferromagnetic layer group 20 includes a second ferromagnetic layer 21 and a coupling layer 22.
  • the second ferromagnetic layer 21 and the coupling layer 22 are adjacent to each other.
  • the second ferromagnetic layer group 20 is magnetically coupled to the first magnetization fixed region 11a.
  • the coupling layer 22 is provided adjacent to the first magnetization fixed region 11a
  • the second ferromagnetic layer 21 is adjacent to the coupling layer 22 and opposite to the first magnetization fixed region 11a. Is provided.
  • the first ferromagnetic layer 10 and the second ferromagnetic layer group 20 have at least a portion of a ferromagnetic material having perpendicular magnetic anisotropy. Further, at least a part of the first magnetization fixed region 11a has a magnetization fixed in an antiparallel direction with respect to at least a part of the second magnetization fixed region 11b.
  • the magnetization free region 12 has reversible magnetization at least partially. This reversible magnetization is oriented in a direction parallel to either the first magnetization fixed region 11a or the second magnetization fixed region 11b. In such a magnetization arrangement, a domain wall is introduced into the first ferromagnetic layer group.
  • the second ferromagnetic layer group 20 includes the second ferromagnetic layer 21 and is magnetically coupled to the first magnetization fixed region 11a. Further, the second ferromagnetic layer group 20 has a magnetization fixed in an antiparallel direction to the magnetization of the first magnetization fixed region 11a at least in part. In order to realize such antiparallel magnetization, the coupling layer 22 magnetically couples the first magnetization fixed region 11a and the second ferromagnetic layer 21 in the antiparallel direction.
  • FIG. 2 schematically shows an example of the magnetization state of the main part of the magnetoresistive effect element according to the present embodiment.
  • the first magnetization fixed region 11a has magnetization fixed in the z-axis positive direction
  • the second magnetization fixed region 11b has magnetization fixed in the z-axis negative direction.
  • the magnetization free region 12 has a magnetization that can take either the z-axis positive or negative direction.
  • the second ferromagnetic layer group 20 provided adjacent to the first magnetization fixed region 11a the second ferromagnetic layer 21 has a negative z-axis that is antiparallel to the magnetization of the first magnetization fixed region 11a. It has a magnetization fixed in the direction.
  • ferromagnetic material used for the first ferromagnetic layer 10 and the second ferromagnetic layer group 20 a Co—Pt alloy is exemplified.
  • An example of the material used for the bonding layer 22 is Ru.
  • a further ferromagnetic layer, nonmagnetic layer, conductive layer, and the like are provided, but these are optional. However, at least one ferromagnetic layer and at least one nonmagnetic layer are provided. These specific forms will be described later.
  • Each layer is desirably provided with a base layer, a cap layer, etc. adjacent to each other as necessary, but this is omitted.
  • a laminated antiferromagnetic coupling (SyAF Coupling) is applied as an initialization method.
  • the laminated ferrimagnetic coupling will be described below with reference to FIGS. 3A and 3B.
  • ferromagnetic ie, a parallel coupling force acts between the ferromagnetic layer A and the ferromagnetic layer B.
  • Increasing the thickness of the coupling layer is ferrimagnetic, that is, an anti-parallel coupling force acts between the ferromagnetic layer A and the ferromagnetic layer B, and further increasing the thickness, ferromagnetic, Repeats ferrimagnetic coupling.
  • by setting the material and film thickness of the coupling layer 22 appropriately antiparallel magnetic coupling can be obtained between the upper and lower layers. The state can be easily initialized.
  • FIG. 4A, FIG. 4B, and FIG. 4C show specific measurement results of the magnetization curve in the laminated film as shown in FIG. 3A and FIG. 3B.
  • a material having perpendicular magnetic anisotropy was used for both the ferromagnetic layer A and the ferromagnetic layer B, and an external magnetic field was applied in a direction perpendicular to the substrate surface.
  • FIG. 4A is a magnetization curve in a certain film configuration.
  • 4B and 4C are magnetization curves in different film configurations, FIG. 4B shows the major loop, and FIG. 4C shows the minor loop.
  • FIG. 4A in the state (1), the ferromagnetic layer A and the ferromagnetic layer B are magnetized in parallel to each other, and this is magnetized in the antiparallel direction in the state of 0 magnetic field in (2). Recognize.
  • FIG. 4B magnetization is performed in the parallel direction in the state of the positive magnetic field (1), magnetized in the anti-parallel state in the state of the negative magnetic field in (2), and when the negative magnetic field is further increased, the parallel magnetization state is obtained again. It can be seen that the transition occurs. Further, as shown in FIG. 4C, it can be seen that in the magnetization curve of FIG. 4B, when the negative magnetic field is reduced from the state of (2) and set to 0, the anti-parallel state is obtained even at 0 magnetic field.
  • FIG. 5 shows an example of a method of initializing the memory state in the structure as shown in FIGS. 1A to 2.
  • FIG. 5 shows an example in which a magnetic field is applied in the ⁇ z direction as the external magnetic field.
  • a sufficiently large external magnetic field is applied to the magnetoresistive element as shown in FIGS. 1A to 2 in the ⁇ z direction.
  • the magnetizations of the second magnetization fixed region 11b and the magnetization free region 12 are oriented in the same direction as the external magnetic field, and are thus magnetized in the ⁇ z direction.
  • the first magnetization fixed region 11a and the second ferromagnetic layer group 20 will be considered.
  • the first magnetization fixed region 11 a is ferrimagnetically coupled to the second ferromagnetic layer 21 through the coupling layer 22.
  • the magnetization of the second ferromagnetic layer 21 is preferentially directed in the direction of the external magnetic field, that is, the ⁇ z direction, whereby the magnetization of the first magnetization fixed region 11a is directed in the opposite direction to the external magnetic field, that is, the + z direction. In this way, the magnetized state as shown in FIG. 5 is realized. As can be seen from FIG.
  • a single domain wall is introduced into the first ferromagnetic layer 10, which means one memory state in the magnetoresistive element.
  • the initialization method as shown in FIG. 5 can be applied when the magnetization curve of the laminated film formed of the first magnetization fixed region 11a and the second ferromagnetic layer group 20 has a shape as shown in FIG. 4A. .
  • the memory state can be initialized by various initialization methods. First, when a sufficiently large external magnetic field is applied in the ⁇ z direction, all magnetizations are directed in the external magnetic field direction, that is, the ⁇ z direction. This state corresponds to the state (1) in the magnetization curve of FIG. 4C. Next, even when this external magnetic field is set to 0, all the magnetizations remain in the ⁇ z direction as shown in FIG. 6A. This corresponds to the state (1) ′ in the magnetization curve of FIG. 4C.
  • FIG. 6B a relatively small external magnetic field is applied in the + z direction.
  • an antiparallel state corresponding to (2) of the magnetization curve of FIG. 4C is realized, and only the magnetization of the first magnetization fixed region 11a is directed in the + z direction.
  • the antiparallel state corresponding to (3) of the magnetization curve in FIG. 4C is maintained, and the magnetization state as shown in FIG. 6B is realized.
  • a single domain wall is introduced into the first ferromagnetic layer 10, which means that the memory state is initialized.
  • the above-described conditions relating to the product of the saturation magnetization and the film thickness are not essential in the present invention. So far, the case where the product of the saturation magnetization and the film thickness of the second ferromagnetic layer 21 is larger than the product of the saturation magnetization and the film thickness of the first magnetization fixed region 11a has been described. A case where the product of the saturation magnetization and the film thickness of the second ferromagnetic layer 21 is smaller than the product of the saturation magnetization and the film thickness of the first magnetization fixed region 11a will be described. In this case, when a sufficiently large magnetic field is first applied in the downward direction, the magnetization of all regions is directed downward.
  • the magnetization of the second ferromagnetic layer 21 having a small product of the saturation magnetization and the film thickness is directed to the external magnetic field direction, that is, the upward direction.
  • the second magnetization fixed region 11b and the magnetization free region 12 have less antiparallel magnetic coupling with the second ferromagnetic layer 21 than the first magnetization fixed region 11a. Inversion occurs earlier, and the magnetizations of the second magnetization fixed region 11b and the magnetization free region 12 are directed upward. At this time, a domain wall is formed at the boundary between the first magnetization fixed region 11 a and the magnetization free region 12.
  • the memory state can be initialized.
  • the memory state may be initialized by applying an external magnetic field in several steps.
  • the external magnetic field may have an in-plane direction component.
  • FIGS. 7A and 7B show an example of the method.
  • FIG. 7A shows a method of writing “1” from the “0” state
  • FIG. 7B shows a method of writing “0” from the “1” state.
  • the magnetization of the first magnetization fixed region 11a is fixed upward
  • the magnetization of the second magnetization fixed region 11b is fixed downward
  • the magnetization of the magnetization free region 12 is directed downward.
  • a state where the magnetization of the magnetization free region 12 is directed upward is defined as a “1” state.
  • the definition of “0” state and “1” state is not limited to this.
  • a domain wall (DW) is formed at the boundary between the first magnetization fixed region 11 a and the magnetization free region 12 in the “0” state.
  • a write current is introduced in the direction from the second magnetization fixed region 11b to the first magnetization fixed region 11a via the magnetization free region 12.
  • the conduction electrons flow from the first magnetization fixed region 11a to the second magnetization fixed region 11b via the magnetization free region 12.
  • the conduction electrons cause current-induced domain wall movement, and the domain wall (DW) moves from the boundary between the first magnetization fixed region 11a and the magnetization free region 12 to the boundary between the second magnetization fixed region 11b and the magnetization free region 12, and FIG. As shown in FIG. In this way, “1” is written.
  • a mechanism in which the domain wall (DW) stops at the boundary between the second magnetization fixed region 11b and the magnetization free region 12 will be described later.
  • a domain wall (DW) is formed at the boundary between the second magnetization fixed region 11b and the magnetization free region 12.
  • a write current is introduced in the direction from the first magnetization fixed region 11a to the second magnetization fixed region 11b via the magnetization free region 12.
  • conduction electrons flow in a direction from the second magnetization fixed region 11b to the first magnetization fixed region 11a via the magnetization free region 12.
  • This conduction electron causes current-induced domain wall movement, and the domain wall (DW) moves from the boundary between the second magnetization fixed region 11b and the magnetization free region 12 to the boundary between the first magnetization fixed region 11a and the magnetization free region 12, and FIG. As shown in FIG. In this way, “0” is written.
  • the first magnetization fixed region 11a and the second magnetization fixed region 11b are preferably connected to different external wirings.
  • the domain wall cannot pass through the boundary between the magnetization fixed region 11 and the magnetization free region 12 and enter the magnetization fixed region 11. This is because the current density decreases in the magnetization fixed region 11. Specifically, it will be described as follows.
  • an electrode for introducing a write current is desirably provided adjacent to the upper surface or the lower surface.
  • 7A and 7B show a structure in which the electrode layer 50 is provided adjacent to the lower surfaces of the first magnetization fixed region 11a and the second magnetization fixed region 11b as an example.
  • the write current flows to the electrode layer 50, and the cross-sectional area perpendicular to the current direction increases outside the boundary between the magnetization fixed region 11 and the magnetization free region 12. Therefore, the current density is reduced and becomes smaller than the threshold current density necessary for the current-induced domain wall movement, so that the domain wall movement does not occur and stops there.
  • the reduction in current density due to such an increase in cross-sectional area can be controlled by modulation of the xy plane shape.
  • the current density outside the boundary between the magnetization fixed region 11 and the magnetization free region 12 can be reduced by setting the width of the magnetization fixed region 11 wider than the width of the magnetization free region 12. A suitable shape for this will be described in a later-described modification.
  • the domain wall stopped at the boundary between the magnetization fixed region 11 and the magnetization free region 12 can stably remain in place. This is because in a material having perpendicular magnetic anisotropy, there are innumerable pinning sites and they have sufficiently large thermal stability.
  • FIGS. 8A and 8B show an example of the method.
  • FIG. 8A shows a reading method in the “0” state
  • FIG. 8B shows a reading method in the “1” state.
  • At least one additional ferromagnetic layer and at least one nonmagnetic layer are provided to read out information.
  • 8A and 8B show an example of the structure of the magnetoresistive element according to this embodiment.
  • the first nonmagnetic layer 30 is provided adjacent to the magnetization free region 12 of the first ferromagnetic layer 10
  • a third ferromagnetic layer 40 is provided adjacent to the nonmagnetic layer 30 on the side opposite to the magnetization free region 12.
  • the first ferromagnetic layer 10, the first nonmagnetic layer 30, and the second ferromagnetic layer 20 form a magnetic tunnel junction (MTJ).
  • MTJ magnetic tunnel junction
  • the first nonmagnetic layer 30 is made of a nonmagnetic material, and preferably made of an insulating material, but may be made of a semiconductor or a metal material. A specific material of the first nonmagnetic layer 30 is exemplified by Al—O.
  • the third ferromagnetic layer 40 is made of a ferromagnetic material having perpendicular magnetic anisotropy. Furthermore, the magnetization of the third ferromagnetic layer 40 is substantially fixed in one direction. Although the third ferromagnetic layer 40 is depicted as a single-layer ferromagnetic layer in FIGS. 8A and 8B, it may actually be formed of a laminated film composed of a plurality of ferromagnetic layers. May include a nonmagnetic layer.
  • Adjacent ferromagnetic layers may be magnetically coupled in the antiparallel direction by a nonmagnetic layer disposed in the middle. Furthermore, the magnetization can be fixed more firmly by making the antiferromagnetic layer adjacent.
  • the laminated structure of the third ferromagnetic layer 40 is exemplified by Co—Pt / Ru / Co—Pt / PtMn.
  • the third ferromagnetic layer 40 (or the vicinity of the interface of the third ferromagnetic layer 40 with the first nonmagnetic layer 30) is fixed downward.
  • FIG. 8A consider the “0” state in which the magnetization free region 12 is magnetized downward. In this state, when current is introduced in a direction penetrating the first ferromagnetic layer 10, the first nonmagnetic layer 30, and the third ferromagnetic layer 40, the magnetizations of the magnetization free region 12 and the third ferromagnetic layer 40 are parallel. Therefore, the MTJ resistance in this case is low.
  • FIG. 8A consider the “0” state in which the magnetization free region 12 is magnetized downward. In this state, when current is introduced in a direction penetrating the first ferromagnetic layer 10, the first nonmagnetic layer 30, and the third ferromagnetic layer 40, the magnetizations of the magnetization free region 12 and the third ferromagnetic layer 40 are parallel. Therefore, the MTJ resistance in this case is low.
  • the positions of the first nonmagnetic layer 30 and the third ferromagnetic layer 40 are arbitrary. In FIGS. 8A and 8B, the first nonmagnetic layer 30 and the third ferromagnetic layer 40 are disposed below the first ferromagnetic layer 10. It does not matter. Moreover, the same side as a 2nd ferromagnetic layer group may be sufficient, and the other side may be sufficient.
  • a perpendicular domain wall motion type MRAM capable of easily initializing a memory state.
  • a method for introducing a domain wall in a perpendicular magnetization film it is conceivable to provide a step as shown in Non-Patent Document 4. That is, regions having different magnetic characteristics are formed by providing a step in the perpendicular magnetization film, and domain walls are introduced by applying an external magnetic field in a plurality of steps using the difference in coercive force between these regions.
  • such a method is not only complicated, but also requires a sufficient margin for the magnetic field into which the domain wall is introduced, and is not suitable for manufacturing a large-scale memory.
  • the domain wall can be introduced by a simple initialization process, and a large initialization magnetic field margin can be easily secured.
  • the write current can be reduced in the perpendicular magnetic domain wall motion type MRAM.
  • the method of pinning the domain wall by a step as used in Non-Patent Document 4 there is a concern that a large leakage magnetic field is applied from the magnetization fixed region in the step region, which becomes an excessive domain wall pinning force. Is done.
  • the influence of the magnetic field on the domain wall pin site is reduced, adjustment can be made so that an excessive domain wall pinning force does not work. This reduces the current density required to depin the domain wall from the pin site, resulting in a reduction in the current value required for writing.
  • the second effect is more effectively brought about by appropriately designing the laminated structure of the second ferromagnetic layer group 20. Details will be described later in the second modification.
  • Circuit configuration Next, a circuit configuration for introducing a write current and a read current in the magnetic memory cell constituted by the magnetoresistive effect element according to the present embodiment will be described.
  • FIG. 9 shows a configuration example of a circuit for one bit of the magnetic memory cell according to the present embodiment.
  • FIG. 9 only the first ferromagnetic layer 10, the first nonmagnetic layer 30, and the third ferromagnetic layer 40 of the magnetoresistive effect element are shown.
  • the terminal connected to the third ferromagnetic layer 40 is connected to the ground line 101 for reading.
  • two terminals connected to the first magnetization fixed region 11a and the second magnetization fixed region 11b are connected to one source / drain of two different transistors 100a and 100b, respectively.
  • the other source / drain of the transistors 100a and 100b is connected to the bit lines 102a and 102b for writing, and the gate electrode is connected to the common word line 103.
  • the magnetic memory cells shown in FIG. 9 are arranged in an array and connected to a peripheral circuit to form a magnetic random access memory (MRAM).
  • MRAM magnetic random access memory
  • the word line 103 is set to “high” and the transistors 100a and 100b are set to “ON”.
  • One of the bit lines 102a and 102b is set to “high”, and the other is set to “ground”. Since the direction of the current flowing through the first ferromagnetic layer 10 changes depending on which bit line 102 is set to “high” and which is set to “ground”, information can be written to the magnetoresistive element. It becomes.
  • the word line 103 is set to “high”, and the transistors 100a and 100b are set to “ON”. Further, the bit line 102a is set to “open”, and the bit line 102b is set to “high”. At this time, a current passing through the magnetoresistive effect element from the bit line 102b flows to the ground line 101 via the first ferromagnetic group layer 10, the first nonmagnetic layer 30, and the third ferromagnetic layer 40. High-speed reading using the effect is possible.
  • the first ferromagnetic layer 10 and the second ferromagnetic layer group 30 include a ferromagnetic layer having perpendicular magnetic anisotropy.
  • These ferromagnetic layers are composed of a ferromagnetic material including at least one material selected from Fe, Co, and Ni.
  • perpendicular magnetic anisotropy can be stabilized by including Pt and Pd.
  • Re, Os, Ir, Au, Sm or the like it is possible to adjust so that desired magnetic properties are expressed.
  • Co Co, Co—Pt, Co—Pd, Co—Cr, Co—Pt—Cr, Co—Cr—Ta, Co—Cr—B, Co—Cr—Pt—B, Co—Cr—Ta— B, Co-V, Co-Mo, Co-W, Co-Ti, Co-Ru, Co-Rh, Fe-Pt, Fe-Pd, Fe-Co-Pt, Fe-Co-Pd, Sm-Co, Examples thereof include Gd—Fe—Co, Tb—Fe—Co, and Gd—Tb—Fe—Co.
  • the magnetic anisotropy in the perpendicular direction can also be exhibited by laminating a layer containing any one material selected from Fe, Co, and Ni with different layers. Specifically, a laminated film of Co / Pd, Co / Pt, Co / Ni, Fe / Au, and the like are exemplified.
  • the first nonmagnetic layer 30 is preferably made of an insulating material. Specifically, Mg—O, Al—O, Al—N, Ni—O, Hf—O and the like are exemplified. However, the present invention can also be implemented using a semiconductor or a metal material. Specifically, Al, Cr, Cu and the like are exemplified.
  • the antiferromagnetic layer is adjacent to the third ferromagnetic layer 40, so that the magnetization can be fixed more firmly.
  • Specific examples of the antiferromagnetic material include Pt—Mn, Ir—Mn, and Fe—Mn.
  • the bonding layer 22 is preferably made of a material that exhibits RKKY interaction. Specifically, Ru, Cr, Cu, Ir, Os, Re, etc. are illustrated.
  • FIG. 10A and 10B schematically show the structure of a first modification of the magnetoresistance effect element according to the present invention.
  • the first modification relates to the position of the second ferromagnetic layer group 20.
  • FIG. 10A is a perspective view
  • FIG. 10B shows an xz sectional view in the xyz coordinate system shown in FIG. 10A.
  • the second ferromagnetic layer group 20 is provided adjacent to the first magnetization fixed region 11a, but this position is optional. That is, FIGS. 1A to 1C show an example in which the second ferromagnetic layer group 20 is disposed above the first ferromagnetic layer 10, as shown in FIGS. 10A and 10B. It may be on the lower side.
  • FIG. 10C shows a cross-sectional view of another embodiment related to the first modification.
  • a Co-based alloy is known as a material having perpendicular magnetic anisotropy, and Ru is often used as a base layer of the Co-based alloy.
  • FIG. 10C shows an example in which the coupling layer 22 also serves as the underlayer of the first ferromagnetic layer 10.
  • Ru or the like as the coupling layer 22
  • the second ferromagnetic layer 21 and the first ferromagnetic layer 10 are coupled by laminated ferrimagnetic coupling, and at the same time, the first ferromagnetic layer 10 is used as an underlayer of the first ferromagnetic layer 10.
  • the crystal orientation of the layer 10 can be adjusted.
  • (Second modification) 11A to 13 schematically show the structure of a second modification of the magnetoresistance effect element according to the present invention.
  • the second modification relates to the configuration of the second ferromagnetic layer group 20.
  • FIG. 11A is a cross-sectional view showing an example.
  • the second ferromagnetic layer group 20 may be a stacked film including a fourth ferromagnetic layer 23 in addition to the first ferromagnetic layer 10 and the coupling layer 22.
  • the fourth ferromagnetic layer 23 is provided adjacent to the first magnetization fixed region 11a. Adjacent to the fourth ferromagnetic layer 23, a coupling layer 22 and a second ferromagnetic layer 21 are provided in this order on the opposite side to the first magnetization fixed region 11a.
  • the first magnetization fixed region 11 a and the fourth ferromagnetic layer 23 are ferromagnetically coupled, and the second ferromagnetic layer 21 and the fourth ferromagnetic layer 23 are ferrimagnetically coupled via the coupling layer 22. Yes.
  • the RKKY interaction described above is used for the ferrimagnetic magnetic coupling.
  • the product of the saturation magnetization and film thickness of the second ferromagnetic layer 21 is the product of the saturation magnetization and film thickness of the first magnetization fixed region 11a and the saturation magnetization of the fourth ferromagnetic layer 23. It is preferably larger than the sum of the product of film thicknesses. This is because the memory state can be initialized by such a method by applying an external magnetic field similar to the method described with reference to FIG. 5, FIG. 6A or FIG. 6B.
  • FIG. 11B and FIG. 11C the state of the magnetic field formed in the vicinity of the first ferromagnetic layer 10 by the magnetization of the second ferromagnetic layer 21 and the fourth ferromagnetic layer 23 is schematically represented by arrows. 11B and 11C are applied to the first ferromagnetic layer 10. As can be seen from FIGS. 11B and 11C, in the vicinity of the boundary between the first magnetization fixed region 11a and the magnetization free region 12, The magnetic field in the x direction cancels and becomes smaller. There is a concern that the magnetic field in the x direction may cause an excessive pinning force.
  • this modification the excessive pinning force is suppressed, and writing with a smaller current density is possible.
  • the magnitude of this pinning force can be adjusted by appropriately designing the magnetic properties and film thicknesses of the second ferromagnetic layer 21 and the fourth ferromagnetic layer 23.
  • FIG. 12 is a sectional view showing an example of another embodiment of the second modification of the magnetoresistive effect element according to the present invention.
  • the second ferromagnetic layer group 20 is a laminated film including a second coupling layer 24 and a fourth ferromagnetic layer 23 in addition to the first ferromagnetic layer 10 and the first coupling layer 22. Also good.
  • the first coupling layer 22 is provided adjacent to the first magnetization fixed region 11a. Adjacent to the first coupling layer 22, a second ferromagnetic layer 21, a second coupling layer 24, and a fourth ferromagnetic layer 23 are stacked in this order.
  • the first magnetization fixed region 11a and the second ferromagnetic layer 21 are ferrimagnetically coupled via the first coupling layer 22, and the second ferromagnetic layer 21 and the fourth ferromagnetic layer 23 are the second coupling layer. It is ferrimagnetically coupled through 24.
  • the memory state can be initialized by the external magnetic field application process as described above with reference to FIGS.
  • FIG. 13 is a cross-sectional view showing still another embodiment of the second modification of the magnetoresistive element according to the present invention.
  • the second ferromagnetic layer group 20 may be a laminated film including an antiferromagnetic layer 25 in addition to the first ferromagnetic layer 10 and the coupling layer 22.
  • the coupling layer 22 is provided adjacent to the first magnetization fixed region 11a.
  • a second ferromagnetic layer 21 and an antiferromagnetic layer 25 are stacked adjacent to the coupling layer 22 in this order.
  • the first magnetization fixed region 11 a and the second ferromagnetic layer 21 are ferrimagnetically coupled via the coupling layer 22.
  • the antiferromagnetic layer 25 can be made of Pt—Mn, Ir—Mn, Fe—Mn, or the like.
  • FIG. 14A to 17 schematically show the structure of a third modification of the magnetoresistance effect element according to the present invention.
  • a plurality of second ferromagnetic layer groups 20 are provided.
  • FIG. 14A is a perspective view
  • FIG. 14B shows an xy plan view in the xyz coordinate system shown in FIG. 14A.
  • FIGS. 15 to 17 show xz sectional views in the xyz coordinate system shown in FIG. 14A, which show different embodiments in the third modification.
  • a plurality of second ferromagnetic layer groups 20 may be provided.
  • the 2-1 ferromagnetic layer group 20a is provided adjacent to the first magnetization fixed region 11a, and the other is adjacent to the second magnetization fixed region 11b.
  • An example is shown in which a 2-2 ferromagnetic layer group 20b, which is a ferromagnetic layer group, is provided.
  • the 2-1 ferromagnetic layer group 20a is formed of the 2-1 ferromagnetic layer 21a and the 1-1 coupling layer 22a
  • the 2-2 ferromagnetic layer group 20b is the 2-2 ferromagnetic layer.
  • An example formed from 21b and the 1-2 coupling layer 22b is shown.
  • the first magnetization fixed region 11a and the 2-1 ferromagnetic layer 21a are ferrimagnetically coupled via the 1-1 coupling layer 22a, and the second magnetization fixed region 11b and the 2-2 ferromagnetic layer 21b are coupled.
  • the saturation magnetization or film thickness of the 2-1 ferromagnetic layer 21a and the 2-2 ferromagnetic layer 21b are preferably different. More preferably, the product of the saturation magnetization and the film thickness of the 2-1 ferromagnetic layer 21a is larger than the product of the saturation magnetization and the film thickness of the first magnetization fixed region 11a, while the saturation of the 2-2 ferromagnetic layer 21b. The product of magnetization and film thickness is preferably smaller than the product of saturation magnetization and film thickness of the second magnetization fixed region 11b.
  • the product of the saturation magnetization and the film thickness of the 2-1 ferromagnetic layer 21a is larger than the product of the saturation magnetization and the film thickness of the first magnetization fixed region 11a. Therefore, the magnetization of the 2-1 ferromagnetic layer 21a faces the -z direction, which is the direction of the external magnetic field, and the magnetization of the first magnetization fixed region 11a ferricoupled to it faces the + z direction, which is the antiparallel direction.
  • the product of the saturation magnetization and the film thickness of the 2-2 ferromagnetic layer 21b is smaller than the product of the saturation magnetization and the film thickness of the second magnetization fixed region 11b.
  • the magnetization of the second magnetization fixed region 11b faces the ⁇ z direction that is the direction of the external magnetic field, and the magnetization of the 2-2 ferromagnetic layer 21b that is ferricoupled to the second magnetization fixed region 11b faces the + z direction that is the antiparallel direction. In this way, the magnetizations of the first magnetization fixed region 11a and the second magnetization fixed region 11b can be directed in the antiparallel direction.
  • FIG. 16 shows an example of another embodiment of the third modification.
  • the 2-1 ferromagnetic layer group 20a is formed of a 2-1 ferromagnetic layer 21a, a 1-1 coupling layer 22a, and a 4-1 ferromagnetic layer 23a
  • -2 shows an example in which the ferromagnetic layer group 20b is formed of the 4-2 ferromagnetic layer 23b.
  • the product of the saturation magnetization and the film thickness of the 2-1 ferromagnetic layer 21a is the product of the saturation magnetization and the film thickness of the first magnetization fixed region 11a and the 4-1 ferromagnetic layer 23a. It is preferably larger than the sum of the product of saturation magnetization and film thickness. This is because the memory state can be initialized by such a method by applying an external magnetic field similar to the method described with reference to FIG. 5, FIG. 6A or FIG. 6B. Details thereof will be omitted because they are obvious from the above description.
  • FIG. 17 shows still another example of the third modification.
  • the 2-1 ferromagnetic layer group 20a is formed of a 2-1 ferromagnetic layer 21a and a 1-1 coupling layer 22a, and the 2-2 ferromagnetic layer group 20b An example formed from the 2-2 ferromagnetic layer 21b is shown.
  • the product of the saturation magnetization and the film thickness of the 2-1 ferromagnetic layer 21a is larger than the product of the saturation magnetization and the film thickness of the first magnetization fixed region 11a. This is because the memory state can be initialized by such a method by applying an external magnetic field similar to the method described with reference to FIG. 5, FIG. 6A or FIG. 6B. Details thereof will be omitted because they are obvious from the above description.
  • the magnetizations of the first magnetization fixed region 11a and the second magnetization fixed region 11b can be more firmly fixed.
  • the margin of the external magnetic field for initialization can be expanded.
  • FIGS. 18B and 18C show an xy plan view and an xz cross-sectional view in the xyz coordinate system shown in FIG. 18A, respectively.
  • the MTJ at this time may not include the third ferromagnetic layer 40 as shown in FIGS. 8A and 8B.
  • 18A, 18B, and 18C in addition to the first ferromagnetic layer 10, the fifth ferromagnetic layer 210, the second nonmagnetic layer 220, and the sixth ferromagnetic layer 230 are used. Is provided.
  • a contact layer 240 is preferably provided.
  • the fifth ferromagnetic layer 210, the second nonmagnetic layer 220, and the sixth ferromagnetic layer 230 are provided adjacent to each other in this order, thereby forming a magnetic tunnel junction (MTJ).
  • MTJ magnetic tunnel junction
  • the center of gravity of the fifth ferromagnetic layer 210 is shifted from the center of gravity 12 of the magnetization free region 12 of the first ferromagnetic layer 10 in the xy plane.
  • the direction of this shift is defined as the first direction.
  • the center of gravity indicates a geometric center of gravity, but since each layer has a substantially uniform density, it may be considered to be a center of gravity.
  • the fifth ferromagnetic layer 210 and the sixth ferromagnetic layer 230 are made of a ferromagnetic material having magnetic anisotropy in the in-plane direction.
  • the direction of magnetic anisotropy of the fifth ferromagnetic layer 210 is arbitrary in the in-plane direction.
  • the magnetization of the sixth ferromagnetic layer 230 is substantially fixed in one direction. This direction is preferably parallel to the first direction.
  • the information stored in the direction of magnetization in the perpendicular direction of the magnetization free region 12 is the surface constituted by the fifth ferromagnetic layer 210, the second nonmagnetic layer 220, and the sixth ferromagnetic layer 230. It can be read by an MTJ having internal magnetization.
  • the principle will be described with reference to FIGS. 19A and 19B.
  • 19A shows the magnetization state of each layer in the “0” state by arrows
  • FIG. 19B shows the magnetization state in the “1” state by arrows.
  • the magnetizations of the first magnetization fixed region 11a, the second magnetization fixed region 11b, and the sixth ferromagnetic layer 230 are depicted as being fixed in the positive z-axis direction, negative direction, and negative y-axis direction, respectively. However, there is arbitraryness between them. Since this optionality is obvious, it is omitted.
  • the magnetization of the fifth ferromagnetic layer 210 is negative in the y-axis due to the leakage magnetic flux generated by the magnetization in the magnetization free region 12 in the downward direction. Turn to the direction. This is because the fifth ferromagnetic layer 210 is arranged below the magnetization free region 12 (in the negative z-axis direction), and the center of gravity of the fifth ferromagnetic layer 210 is in the negative y-axis direction with respect to the magnetization free region 12. This is because they are provided in a shifted manner.
  • the magnetizations of the fifth ferromagnetic layer 210 and the sixth ferromagnetic layer 230 become parallel, and this MTJ enters a low resistance state.
  • the magnetization of the fifth ferromagnetic layer 210 is y by the leakage magnetic flux generated by the upward magnetization of the magnetization free region 12. Direct in the positive direction.
  • the magnetizations of the fifth ferromagnetic layer 210 and the sixth ferromagnetic layer 230 become antiparallel, and this MTJ is in a high resistance state.
  • the information stored as the magnetization in the perpendicular direction of the magnetization free region 12 is transmitted to the magnetization of the fifth ferromagnetic layer 210 having the in-plane magnetization, and can be read out by the MTJ composed of the in-plane magnetization.
  • MR ratio magnetoresistive effect ratio
  • the fifth ferromagnetic layer 210, the second nonmagnetic layer 220, and the sixth ferromagnetic layer 230 are disposed on the lower side (z-axis negative direction) with respect to the first ferromagnetic layer 10.
  • this position is arbitrary and may be, for example, the upper side.
  • the first direction which is the direction of deviation of the center of gravity of the fifth ferromagnetic layer 210 from the center of gravity of the magnetization free region 12, is drawn as a negative y-axis direction in the figure, but this is also arbitrary. And may be in the positive y-axis direction or may contain an x component.
  • (Fifth modification) 20A to 22B schematically show the structure of a fifth modification of the magnetoresistance effect element according to the present invention.
  • the fifth modification relates to the shape of the first ferromagnetic layer 10.
  • the shape of the first ferromagnetic layer 10 is arbitrary.
  • the first ferromagnetic layer 10 is depicted as having a rectangular shape in the xy plane, but FIGS. 20A to 22B show modifications regarding the shape of the first ferromagnetic layer 10.
  • 20A, 20B, 21A, 21B, and 22B show xy plan views.
  • FIG. 22A shows a perspective view of the first ferromagnetic layer 10 having the shape as shown in FIG. 22B.
  • the first ferromagnetic layer 10 may be provided with a notch as shown in FIG. 20A, for example. By providing this notch at the boundary between the first magnetization fixed region 11a and the magnetization free region 12 and at the boundary between the second magnetization fixed region 11b and the magnetization free region 12, the pinning position of the domain wall can be clearly defined.
  • the first ferromagnetic layer 10 may be formed so that the central portion is thick as shown in FIG. 20B.
  • the domain wall has the property of moving as narrow as possible in order to lower the energy of the entire system. However, by forming the center part thick as shown in FIG. 20B, the domain wall is less likely to stop at the center part, and a stable binary value is obtained. A state is realized.
  • the magnetization fixed region 11 may be formed thicker than the magnetization free region 12 as shown in FIGS. 21A and 21B.
  • FIG. 21A shows an example in which both the first magnetization fixed region 11a and the second magnetization fixed region 11b are formed thick.
  • FIG. 21B shows an example in which only the second magnetization fixed region 11b is formed thick.
  • the first ferromagnetic layer 10 may be formed in a Y shape as shown in FIGS. 22A and 22B. 22A and 22B, the first ferromagnetic layer 10 includes a magnetization free region 12 provided extending in the x direction, and a first magnetization fixed region provided connected to one end ( ⁇ x side) thereof. 11a and a second magnetization fixed region 11b provided in the same manner connected to one end. That is, the first ferromagnetic layer 10 forms a three-way path. Also in this case, the magnetizations of the first magnetization fixed region 11a and the second magnetization fixed region 11b are fixed at least partially in the vertical direction and in antiparallel directions. In addition, the magnetization of the magnetization free region 12 is either vertical or vertical.
  • FIG. 23A schematically shows a method of writing “1” from the “0” state
  • FIG. 23B schematically shows a method of writing “0” from the “1” state.
  • the domain wall (DW) moves to the side opposite to the end connected to the first magnetization fixed region 11a of the magnetization free region 12 due to the current induced domain wall movement phenomenon.
  • Transition to the “1” state as shown in FIG. Similarly, in the “1” state in which the magnetization free region 12 is magnetized upward as shown in FIG. 23B, a domain wall (DW) is formed at the boundary between the second magnetization fixed region 11 b and the magnetization free region 12. If a current is passed in the direction of the dotted line in FIG. 23B, the domain wall (DW) moves to the opposite side to the end of the magnetization free region 12 connected to the second magnetization fixed region 11b due to the phenomenon of current induced domain wall movement. , Transition to a “0” state as shown in FIG. 23A. In this way, information can be rewritten.
  • Writing is performed by forming the first ferromagnetic layer 10 in a three-way shape as shown in FIG. 22A and FIG. 22B and extracting the domain wall at the end of the magnetization free region 12. By such a writing process, a more stable writing operation can be realized.
  • Examples of utilization of the present invention include nonvolatile semiconductor memory devices used in mobile phones, mobile personal computers and PDAs, and microcomputers with built-in nonvolatile memory used in automobiles and the like.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Mram Or Spin Memory Techniques (AREA)
  • Hall/Mr Elements (AREA)

Abstract

L'élément à effet magnétorésistif est pourvu d'une première couche ferromagnétique et d'un groupe de secondes couches ferromagnétiques qui sont réalisées en un matériau ferromagnétique ayant au moins une anisotropie magnétique perpendiculaire partielle. La première couche ferromagnétique comporte au moins une première zone de magnétisation fixée, une deuxième zone de magnétisation fixée et une zone de magnétisation libre. Le groupe de deuxièmes couches ferromagnétiques est pourvu d'au moins une deuxième couche ferromagnétique et d'une première couche de couplage. La magnétisation de la première zone de magnétisation fixée et de la deuxième zone de magnétisation fixée implique une composante qui est au moins partiellement fixée dans la direction antiparallèle. La magnétisation de la première zone de magnétisation fixée et de la deuxième couche ferromagnétique implique une composante qui est au moins partiellement fixée dans la direction antiparallèle. Au moyen d'une telle configuration, il est possible de réaliser une mémoire magnétique à accès aléatoire qui permet d'initialiser l'état de la mémoire facilement tout en utilisant un déplacement de paroi de domaine commandé par courant.
PCT/JP2009/056044 2008-04-02 2009-03-26 Elément à effet magnétorésistif et mémoire magnétique à accès aléatoire Ceased WO2009122990A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2010505748A JP5445970B2 (ja) 2008-04-02 2009-03-26 磁気抵抗効果素子及び磁気ランダムアクセスメモリ

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2008-095757 2008-04-02
JP2008095757 2008-04-02

Publications (1)

Publication Number Publication Date
WO2009122990A1 true WO2009122990A1 (fr) 2009-10-08

Family

ID=41135370

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2009/056044 Ceased WO2009122990A1 (fr) 2008-04-02 2009-03-26 Elément à effet magnétorésistif et mémoire magnétique à accès aléatoire

Country Status (2)

Country Link
JP (1) JP5445970B2 (fr)
WO (1) WO2009122990A1 (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011052475A1 (fr) * 2009-10-26 2011-05-05 日本電気株式会社 Élément de mémoire magnétique, mémoire magnétique et procédés d'initialisation de l'élément de mémoire magnétique et de la mémoire magnétique
WO2013190924A1 (fr) * 2012-06-21 2013-12-27 日本電気株式会社 Dispositif à semi-conducteur et son procédé de fabrication
WO2014168012A1 (fr) * 2013-04-10 2014-10-16 日本電気株式会社 Dispositif à semi-conducteurs et procédé pour fabriquer celui-ci
JP2015060609A (ja) * 2013-09-18 2015-03-30 株式会社東芝 磁気記憶装置及びその駆動方法
JP2015068990A (ja) * 2013-09-30 2015-04-13 日本放送協会 空間光変調器
WO2020230877A1 (fr) * 2019-05-15 2020-11-19 Tdk株式会社 Élément de mouvement de paroi de domaine, réseau d'enregistrement magnétique et dispositif à semi-conducteur
JP2022034728A (ja) * 2020-08-19 2022-03-04 Tdk株式会社 配線層、磁壁移動素子および磁気アレイ
WO2022070378A1 (fr) * 2020-10-01 2022-04-07 Tdk株式会社 Élément de déplacement de paroi de domaine et réseau magnétique

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7666919B2 (ja) 2020-12-15 2025-04-22 Tdk株式会社 磁壁移動素子及び磁気アレイ

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004158578A (ja) * 2002-11-05 2004-06-03 Toshiba Corp 磁気記憶装置及びその製造方法
WO2005069368A1 (fr) * 2004-01-15 2005-07-28 Japan Science And Technology Agency Element mobile de paroi de domaine magnetique a injection de courant
JP2006504210A (ja) * 2002-03-27 2006-02-02 イーストゲイト インベストメンツ リミテッド データ記憶装置
JP2006073930A (ja) * 2004-09-06 2006-03-16 Canon Inc 磁壁移動を利用した磁気抵抗効果素子の磁化状態の変化方法及び該方法を用いた磁気メモリ素子、固体磁気メモリ
JP2006303159A (ja) * 2005-04-20 2006-11-02 Fuji Electric Holdings Co Ltd スピン注入磁区移動素子およびこれを用いた装置
JP2009054715A (ja) * 2007-08-24 2009-03-12 Nec Corp 磁壁ランダムアクセスメモリ

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007119446A1 (fr) * 2006-03-24 2007-10-25 Nec Corporation Procédé de lecture/écriture de données mram et mram

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006504210A (ja) * 2002-03-27 2006-02-02 イーストゲイト インベストメンツ リミテッド データ記憶装置
JP2004158578A (ja) * 2002-11-05 2004-06-03 Toshiba Corp 磁気記憶装置及びその製造方法
WO2005069368A1 (fr) * 2004-01-15 2005-07-28 Japan Science And Technology Agency Element mobile de paroi de domaine magnetique a injection de courant
JP2006073930A (ja) * 2004-09-06 2006-03-16 Canon Inc 磁壁移動を利用した磁気抵抗効果素子の磁化状態の変化方法及び該方法を用いた磁気メモリ素子、固体磁気メモリ
JP2006303159A (ja) * 2005-04-20 2006-11-02 Fuji Electric Holdings Co Ltd スピン注入磁区移動素子およびこれを用いた装置
JP2009054715A (ja) * 2007-08-24 2009-03-12 Nec Corp 磁壁ランダムアクセスメモリ

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011052475A1 (fr) * 2009-10-26 2011-05-05 日本電気株式会社 Élément de mémoire magnétique, mémoire magnétique et procédés d'initialisation de l'élément de mémoire magnétique et de la mémoire magnétique
JPWO2011052475A1 (ja) * 2009-10-26 2013-03-21 日本電気株式会社 磁気メモリ素子、磁気メモリ、及びその初期化方法
US8592930B2 (en) 2009-10-26 2013-11-26 Nec Corporation Magnetic memory element, magnetic memory and initializing method
WO2013190924A1 (fr) * 2012-06-21 2013-12-27 日本電気株式会社 Dispositif à semi-conducteur et son procédé de fabrication
JPWO2013190924A1 (ja) * 2012-06-21 2016-05-26 日本電気株式会社 半導体装置及びその製造方法
US9406869B2 (en) 2012-06-21 2016-08-02 Nec Corporation Semiconductor device
WO2014168012A1 (fr) * 2013-04-10 2014-10-16 日本電気株式会社 Dispositif à semi-conducteurs et procédé pour fabriquer celui-ci
JPWO2014168012A1 (ja) * 2013-04-10 2017-02-16 日本電気株式会社 半導体装置及びその製造方法
JP2015060609A (ja) * 2013-09-18 2015-03-30 株式会社東芝 磁気記憶装置及びその駆動方法
JP2015068990A (ja) * 2013-09-30 2015-04-13 日本放送協会 空間光変調器
WO2020230877A1 (fr) * 2019-05-15 2020-11-19 Tdk株式会社 Élément de mouvement de paroi de domaine, réseau d'enregistrement magnétique et dispositif à semi-conducteur
JPWO2020230877A1 (fr) * 2019-05-15 2020-11-19
CN113366662A (zh) * 2019-05-15 2021-09-07 Tdk株式会社 磁畴壁移动元件、磁记录阵列和半导体装置
JP7173311B2 (ja) 2019-05-15 2022-11-16 Tdk株式会社 磁壁移動素子、磁気記録アレイ及び半導体装置
CN113366662B (zh) * 2019-05-15 2023-08-29 Tdk株式会社 磁畴壁移动元件、磁记录阵列和半导体装置
US11790967B2 (en) 2019-05-15 2023-10-17 Tdk Corporation Magnetic domain wall displacement element, magnetic recording array, and semiconductor device
JP2022034728A (ja) * 2020-08-19 2022-03-04 Tdk株式会社 配線層、磁壁移動素子および磁気アレイ
JP7470599B2 (ja) 2020-08-19 2024-04-18 Tdk株式会社 配線層、磁壁移動素子および磁気アレイ
WO2022070378A1 (fr) * 2020-10-01 2022-04-07 Tdk株式会社 Élément de déplacement de paroi de domaine et réseau magnétique
JP2022059565A (ja) * 2020-10-01 2022-04-13 Tdk株式会社 磁壁移動素子および磁気アレイ
JP7670581B2 (ja) 2020-10-01 2025-04-30 Tdk株式会社 磁壁移動素子および磁気アレイ

Also Published As

Publication number Publication date
JPWO2009122990A1 (ja) 2011-07-28
JP5445970B2 (ja) 2014-03-19

Similar Documents

Publication Publication Date Title
CN101689600B (zh) 磁阻效应元件及磁性随机存取存储器
JP6304697B2 (ja) 磁気メモリ素子および磁気メモリ
JP5370907B2 (ja) 磁気抵抗効果素子、及び磁気ランダムアクセスメモリ
JP5224127B2 (ja) 磁気抵抗効果素子、および磁気ランダムアクセスメモリ
JP5445970B2 (ja) 磁気抵抗効果素子及び磁気ランダムアクセスメモリ
JP5366014B2 (ja) 磁気ランダムアクセスメモリ及びその初期化方法
JP5382348B2 (ja) 磁気抵抗効果素子、及び磁気ランダムアクセスメモリ
US8787076B2 (en) Magnetic memory and method of manufacturing the same
JP5257831B2 (ja) 磁気ランダムアクセスメモリ、及びその初期化方法
US8592930B2 (en) Magnetic memory element, magnetic memory and initializing method
JP5483025B2 (ja) 磁気メモリ素子、磁気メモリ
JP5397384B2 (ja) 磁性記憶素子の初期化方法
JPWO2012002156A1 (ja) 磁気メモリ素子、磁気メモリ
JP5397224B2 (ja) 磁気抵抗効果素子、及び磁気ランダムアクセスメモリ、及びその初期化方法
JP5370773B2 (ja) 磁気抵抗効果素子、及び磁気ランダムアクセスメモリ、及びその初期化方法
JP2010098259A (ja) メモリセル、ならびに、磁気メモリ素子
JP2012028489A (ja) 磁気記憶装置
JPWO2009133744A1 (ja) 磁気記憶素子、及び磁気メモリ
US20130075847A1 (en) Magnetic memory
JPWO2012137911A1 (ja) 磁気抵抗効果素子、及び磁気ランダムアクセスメモリ

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 09727063

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2010505748

Country of ref document: JP

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 09727063

Country of ref document: EP

Kind code of ref document: A1