JP2019186280A - Magnetoresistive effect device - Google Patents

Abstract

A magnetoresistive device capable of reducing a differential mode current flowing in a differential transmission line is provided. A magnetoresistive effect device of the present invention connects a first port for inputting a high-frequency signal, a second port for outputting a high-frequency signal, and a first port and a second port to form a differential transmission line. , A first signal line 104 and a second signal line 105, a magnetoresistive element 106 connected to each of the first signal line 104 and the second signal line 105, a first signal line 104 and a second signal line And a DC application terminal connected to the first and second signal lines 105, 105, and the magnetoresistive effect element 106 is disposed on one side of the plane P1 including the first signal line 104 and the second signal line 105. The layer and the magnetization free layer are stacked perpendicular to the plane P1, and the axis of easy magnetization of the magnetization fixed layer is perpendicular to the stacking surface of the magnetoresistive element. [Selection diagram] Fig. 1

Description

  The present invention relates to a magnetoresistive device.

  In recent years, with the enhancement of functions of mobile communication terminals such as mobile phones, the speed of wireless communication has been increased. Since the communication speed is proportional to the bandwidth of the frequency to be used, the frequency band necessary for communication is increased, and accordingly, the number of high-frequency filters required for the mobile communication terminal is increased. In addition, research in the field of spintronics, which is expected to be applied to new high frequency components, has been actively conducted. One of the phenomena attracting attention is a ferromagnetic resonance phenomenon caused by a magnetoresistive effect element (see Non-Patent Document 1).

  For example, by applying an alternating current to the magnetoresistive effect element and applying a static magnetic field using a magnetic field application mechanism, ferromagnetic resonance can be caused in the magnetization of the magnetization free layer included in the magnetoresistive effect element. . At this time, the resistance value of the magnetoresistive element vibrates periodically at a frequency corresponding to the ferromagnetic resonance frequency. The ferromagnetic resonance frequency varies depending on the strength of the static magnetic field applied to the magnetoresistive element, and the resonance frequency is generally included in a high frequency band of several to several tens of GHz (see Patent Document 1).

JP 2017-63397 A

Journal Of Applied Physics 99, 08N503, 17 November 2006

  In a high-frequency circuit, a pair of signal lines that make up a differential transmission line are usually used by flowing currents in the opposite directions (differential mode currents) having the same size. However, currents (common mode currents) that are the same in magnitude and flow in the same direction may flow through each signal line due to the connection state with the device and the like. Such a current causes radiation noise generation, so it needs to be reduced.

  When taking measures to reduce the common mode current, it is required to quantitatively grasp how much the common mode current flows in a specific signal line. For this purpose, a technique for temporarily interrupting (reducing) the differential mode current is required.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a magnetoresistive effect device capable of reducing a differential mode current flowing in a differential transmission line.

  The present invention provides the following means in order to solve the above problems.

(1) A magnetoresistive effect device according to one aspect of the present invention connects a first port for inputting a high-frequency signal, a second port for outputting a high-frequency signal, the first port and the second port, A first signal line and a second signal line constituting a differential transmission line; a magnetoresistive effect element connected to each of the first signal line and the second signal line; the first signal line and the second signal line; A DC application terminal connected to the signal line, and the magnetoresistive effect element includes a magnetization fixed layer, a magnetization free layer, and a spacer layer sandwiched between the magnetization fixed layer and the magnetization free layer, respectively. The magnetoresistive effect element is laminated perpendicularly to a plane including the first signal line and the second signal line, and the magnetoresistive element is formed on the first signal line and the second signal line in a plan view from the lamination direction. Arranged to be pinched Are easy magnetization axis of the magnetization fixed layer is perpendicular to the lamination plane of the magnetoresistive element.

(2) A magnetoresistive effect device according to another aspect of the present invention connects a first port for inputting a high-frequency signal, a second port for outputting a high-frequency signal, and the first port and the second port. A first signal line and a second signal line constituting a differential transmission line; a magnetoresistive effect element connected to each of the first signal line and the second signal line; the first signal line; A DC application terminal connected to the second signal line, and the magnetoresistive element is a magnetization fixed layer, a magnetization free layer, and a spacer layer sandwiched between the magnetization fixed layer and the magnetization free layer, respectively. And the magnetoresistive element is disposed so that the magnetization of the magnetization free layer is ferromagnetically resonated by a magnetic field in a direction perpendicular to a plane including the first signal line and the second signal line. ing.

(3) In the magnetoresistive effect device according to (2), the magnetoresistive effect element is disposed so as to be sandwiched between the first signal line and the second signal line in a plan view from the stacking direction. It is preferable.

(4) In the magnetoresistive effect device according to (3), in the plan view from the stacking direction, the magnetoresistive effect element connected to the first signal line is a distance from the first signal line, It is preferable that the distance between the second signal line and the second signal line be equal.

(5) In the magnetoresistive effect device according to any one of (3) and (4), the magnetoresistive effect element connected to the second signal line in the plan view from the stacking direction includes the first It is preferable that the first signal line and the second signal line have the same distance.

(6) In the magnetoresistive effect device according to any one of (1) to (5), it is preferable that the magnetoresistive device includes a frequency control unit that controls a ferromagnetic resonance frequency of magnetization of the magnetization free layer.

(7) In the magnetoresistive effect device according to any one of (1) to (6) above, a plurality of the ferromagnetic resonance frequencies of magnetization of the magnetization free layer different from each other with respect to the first signal line. The magnetoresistive elements are preferably connected in parallel.

(8) In the magnetoresistance effect device according to any one of (1) to (7), a plurality of the ferromagnetic resonance frequencies of magnetization of the magnetization free layer different from each other with respect to the second signal line. The magnetoresistive elements are preferably connected in parallel.

(9) In the magnetoresistance effect device according to any one of (1) to (6), a plurality of the ferromagnetic resonance frequencies of magnetization of the magnetization free layer different from each other with respect to the first signal line. The magnetoresistive elements are preferably connected in series.

(10) In the magnetoresistive effect device according to any one of (1) to (6) and (9) above, the ferromagnetic resonance frequencies of the magnetizations of the magnetization free layer are mutually different with respect to the second signal line. It is preferable that a plurality of different magnetoresistive elements are connected in series.

  In the magnetoresistive effect device of the present invention, the magnetoresistive effect element is arranged on one side of the plane including the first signal line and the second signal line constituting the differential transmission line, and the laminated surface is perpendicular to the plane. It has become. Therefore, when a differential mode current flows through the first signal line and the second signal line, a magnetic field perpendicular to the laminated surface is applied to the magnetoresistive effect element. The magnetization of the magnetization free layer resonates with the magnetization of the magnetization free layer when it precesses around the direction of the applied magnetic field and the frequency of the differential mode current is close to the resonance frequency of the magnetoresistive element. . Thereby, the impedance of the magnetoresistive effect element with respect to the differential mode current is lowered.

  On the other hand, when a common mode current flows through the first signal line and the second signal line, a magnetic field parallel to the laminated surface is applied to the magnetoresistive effect element. In this case, even if the magnetization of the magnetization free layer precesses around the direction of the applied magnetic field, the magnetization of the magnetization free layer hardly resonates with the magnetization of the magnetization free layer. Will not go down. Therefore, in the magnetoresistive effect device of the present invention, only the differential mode current among the currents flowing through the differential transmission line can flow to the magnetoresistive effect element side, and as a result, the differential mode current flowing through the differential transmission line. Can be reduced.

It is a perspective view of the magnetoresistive effect device concerning a first embodiment of the present invention. It is a figure which shows typically the magnetic field formed of (a), (b) differential mode electric current. (A), (b) It is a figure which shows typically the magnetic field formed with a common mode electric current. It is a figure which shows typically the magnetic field applied to the magnetoresistive effect element of 1st embodiment by differential mode current and common mode current. It is a perspective view of the magnetoresistive effect device which concerns on the modification 1 of this invention. It is a perspective view of the magnetoresistive effect device which concerns on the modification 2 of this invention. It is a perspective view of the magnetoresistive effect device concerning a second embodiment of the present invention. It is a figure which shows typically the magnetic field applied to the magnetoresistive effect element of 2nd embodiment by differential mode current and common mode current. It is a perspective view of the magnetoresistive effect device concerning a third embodiment of the present invention. It is a figure which shows typically the magnetic field applied to the magnetoresistive effect element of 3rd embodiment by differential mode current and common mode current.

  Hereinafter, the present invention will be described in detail with appropriate reference to the drawings. In the drawings used in the following description, in order to make the characteristics of the present invention easier to understand, there are cases where the characteristic parts are enlarged for the sake of convenience, and the dimensional ratios and the like of each component are different from actual ones. is there. The materials, dimensions, and the like exemplified in the following description are merely examples, and the present invention is not limited to these, and can be implemented with appropriate modifications within the scope of the effects of the present invention.

<First embodiment>
FIG. 1 is a perspective view of a magnetoresistive device 100 according to a first embodiment of the present invention. The magnetoresistive effect device 100 mainly connects a first port 101 for inputting a high-frequency signal, a second port 102 for outputting a high-frequency signal, and the first port 101 and the second port 102, and a differential transmission line. 103, the first signal line 104 and the second signal line 105, the magnetoresistive effect element 106 connected to each of the first signal line 104 and the second signal line 105, and the first signal line 104 and the second signal. And a DC application terminal 107 connected to the line 105.

  The differential transmission line 103 has a path connecting the first port 101 and the second port 102 in series via the first signal line 104, and connects the first port 101 and the second port 102 via the second signal line 105. It is configured by a series connection path.

The magnetoresistive effect element 106 is disposed on _one side of the plane P ₁ including the first signal line 104 and the second signal line 105, that is, at a position not intersecting with the plane P ₁ . Here, the plane P ₁ includes a flat space having the same thickness as the first signal line 104 and the second signal line 105. Need not plurality of magnetoresistive elements 106 are arranged aligned on the same side, respectively, it is sufficient arranged on one side of either of the plane P _1.

The magnetoresistive effect element 106 includes a magnetization fixed layer 108, a magnetization free layer 109, a spacer layer 110 sandwiched between the magnetization fixed layer 108 and the magnetization free layer 109, and a first signal line 104 and a second signal line 105. formed by laminating substantially perpendicular to the plane P ₁ including. The magnetoresistive element 106 is arranged so that the magnetization of the magnetization free layer 109 is ferromagnetically resonated by a magnetic field in a direction perpendicular to the plane P ₁ including the first signal line 104 and the second signal line 105.

  The magnetization of the magnetization fixed layer 108 is less likely to change than the magnetization of the magnetization free layer 109 and is fixed in one direction under a predetermined magnetic field environment. The magnetization direction of the magnetization free layer 109 changes relative to the magnetization direction of the magnetization fixed layer 108, thereby functioning as the magnetoresistive effect element 101.

  The magnetization easy axis of the magnetization fixed layer 108 is substantially perpendicular to the laminated surface of the magnetoresistive effect element 106, and the magnetization fixed layer 108 is magnetized in this direction.

  The magnetization fixed layer 108 is made of a ferromagnetic material, and its magnetization direction is substantially fixed in one direction. The magnetization fixed layer 108 is preferably made of a high spin polarizability material such as Fe, Co, Ni, an alloy of Ni and Fe, an alloy of Fe and Co, or an alloy of Fe, Co and B. Thereby, a high magnetoresistance change rate can be obtained. The magnetization fixed layer 108 may be made of a Heusler alloy. The thickness of the magnetization fixed layer 108 is preferably 1 to 10 nm.

The magnetization pinning method of the magnetization pinned layer 108 is not particularly limited. For example, an antiferromagnetic layer may be added so as to be in contact with the magnetization fixed layer 108 in order to fix the magnetization of the magnetization fixed layer 108. Further, the magnetization of the magnetization fixed layer 108 may be fixed using magnetic anisotropy due to the crystal structure, shape, or the like. For the antiferromagnetic layer, FeO, CoO, NiO, CuFeS ₂ , IrMn, FeMn, PtMn, Cr, Mn, or the like can be used.

  The magnetization free layer 109 is made of a ferromagnetic material whose magnetization direction can be changed by an external magnetic field or spin-polarized electrons.

  For the magnetization free layer 109, CoFe, CoFeB, CoFeSi, CoMnGe, CoMnSi, CoMnAl, or the like can be used as a material having an easy axis in the in-plane direction perpendicular to the stacking direction L of the magnetoresistive element 106. Co, CoCr-based alloy, Co multilayer film, CoCrPt-based alloy, FePt-based alloy, SmCo-based alloy containing rare earth, TbFeCo alloy, or the like is used as a material when the magnetization free layer 109 has an easy axis in the stacking direction L. be able to. Moreover, the magnetization free layer 109 may be made of a Heusler alloy.

  The thickness of the magnetization free layer 109 is preferably about 0.5 to 20 nm. Further, a high spin polarizability material may be inserted between the magnetization free layer 109 and the spacer layer 110. By inserting a high spin polarizability material, a high magnetoresistance change rate can be obtained.

  Examples of the high spin polarizability material include a CoFe alloy and a CoFeB alloy. The film thickness of either the CoFe alloy or the CoFeB alloy is preferably about 0.2 to 1.0 nm.

  The spacer layer 110 is preferably made of a nonmagnetic material. The spacer layer 110 is composed of a layer formed of a conductor, an insulator, or a semiconductor, or a layer including a conduction point formed of a conductor in the insulator.

  For example, when the spacer layer 110 is made of an insulator, the magnetoresistive element 106 is a tunneling magnetoresistive (TMR) element, and when the spacer layer 110 is made of metal, a giant magnetoresistance (GMR: It becomes a Giant Magnetometer (element).

When an insulating material is used for the spacer layer 110, an insulating material such as Al ₂ O ₃ or MgO can be used. A high magnetoresistance change rate can be obtained by adjusting the thickness of the spacer layer 110 so that a coherent tunnel effect is developed between the magnetization fixed layer 108 and the magnetization free layer 109. In order to efficiently use the TMR effect, the thickness of the spacer layer 110 is preferably about 0.5 to 3.0 nm.

  When the spacer layer 110 is made of a conductive material, a conductive material such as Cu, Ag, Au, or Ru can be used. In order to efficiently use the GMR effect, the thickness of the spacer layer 110 is preferably about 0.5 to 3.0 nm.

When the spacer layer 110 is made of a semiconductor, a material such as ZnO, In ₂ O ₃ , SnO ₂ , ITO, GaOx, or Ga2Ox can be used. In this case, the thickness of the spacer layer 110 is preferably about 1.0 to 4.0 nm.

When a layer including a conduction point constituted by a conductor in an insulator is applied as the spacer layer 110, an insulator constituted by Al ₂ O ₃ or MgO includes CoFe, CoFeB, CoFeSi, CoMnGe, CoMnSi, and CoMnAl. , Fe, Co, Au, Cu, Al, or a conductor including a conduction point constituted by a conductor such as Mg is preferable. In this case, the thickness of the spacer layer 110 is preferably about 0.5 to 2.0 nm.

  In addition, a cap layer, a seed layer, or a buffer layer may be provided between the upper electrode 111 and the magnetoresistive effect element 106 and between the lower electrode 112 and the magnetoresistive effect element 106. Examples of the cap layer, seed layer, or buffer layer include Ru, Ta, Cu, Cr, or a laminated film thereof. The thickness of these layers is preferably about 2 to 10 nm.

  The size of the magnetoresistive element 106 is preferably about 100 nm or less than 100 nm when the planar shape of the magnetoresistive element 106 is rectangular (including a square). When the planar view shape of the magnetoresistive effect element 106 is not rectangular, the long side of the rectangle circumscribing the planar view shape of the magnetoresistive effect element 106 with the minimum area is defined as the long side of the magnetoresistive effect element 106. To do. When the long side is as small as about 100 nm, the magnetic domain of the magnetization free layer 109 can be made into a single domain, and a highly efficient spin torque resonance phenomenon can be realized. Here, the “planar shape” is a shape viewed in a plane perpendicular to the stacking direction L of each layer constituting the magnetoresistive effect element.

  In order to improve the electrical conductivity to the magnetoresistive effect element 101, it is preferable that electrodes are provided at both ends of the magnetoresistive effect element 106. Here, in the stacking direction L of the magnetoresistive effect element 106, the electrode provided at the upper end is referred to as the upper electrode 111, and the electrode provided at the lower end is referred to as the lower electrode 112. The upper electrode 111 and the lower electrode 112 serve as a pair of electrodes, and are disposed via the magnetoresistive effect element 106 in the stacking direction L of each layer constituting the magnetoresistive effect element 106. That is, the upper electrode 111 and the lower electrode 112 constitute a signal (current) in a direction intersecting the surface of each layer constituting the magnetoresistive effect element 106 with respect to the magnetoresistive effect element 106, for example, the magnetoresistive effect element 106. It functions as a pair of electrodes for flowing in a direction (stacking direction) perpendicular to the surface of each layer. As a material of the upper electrode 111 and the lower electrode 112, for example, a conductive material such as Ta, Cu, Au, AuCu, Ru, or Al can be used.

  One end (magnetization free layer 109 side) of the magnetoresistive effect element 106 is electrically connected to either the first signal line 104 or the second signal line 105 via the upper electrode 111, and the other end (magnetization fixed). The layer 108 side) is electrically connected to the ground 115 through the lower electrode 112. The magnetoresistive effect element 106 is preferably connected to each of the first signal line 104 and the second signal line 105 so as to be parallel to the second port 102.

  The ground 115 functions as a reference potential. The shapes of the differential transmission line 103 and the ground 115 are preferably defined as a microstrip line (MSL) type or a coplanar waveguide (CPW) type. When designing a microstrip line shape or a coplanar waveguide shape, the signal line widths of the first signal line 104 and the second signal line 105 and the distance between the ground so that the characteristic impedance of the differential transmission line 103 is equal to the impedance of the circuit system. By designing the distance, a differential transmission line with little transmission loss can be obtained.

  The DC application terminal 107 is connected between the magnetoresistive effect element 106 and the first port 101 in each of the first signal line 104 and the second signal line 105. The DC application terminal 107 is connected to the power supply 113 and applies a DC current or a DC voltage in the stacking direction L of the magnetoresistive effect element 101. In this specification, the direct current is a current whose direction does not change with time, and includes a current whose magnitude changes with time. The DC voltage is a voltage whose direction does not change with time, and includes a voltage whose magnitude changes with time. The power source 113 may be a direct current source or a direct current voltage source.

  By connecting the power supply 113 to the DC application terminal 107, it becomes possible to apply a DC current to the magnetoresistive element 106. In the magnetoresistance effect device 100 shown in FIG. 1, a direct current flowing in the direction from the magnetization free layer 109 to the magnetization fixed layer 108 is applied to the magnetoresistance effect element 106. Further, a choke coil or a resistance element for cutting a high-frequency signal may be connected in series between the DC application terminal 107 and the power supply 113.

  A magnetic field application mechanism 114 that applies a magnetic field to the magnetoresistive effect element 106 may be provided in the vicinity of the magnetoresistive effect element 106. As the magnetic field application mechanism 114, an electromagnet type capable of variably controlling the applied magnetic field intensity by either voltage or current, a stripline type, or the like can be used. Further, as the magnetic field application mechanism 114, a mechanism constituted by a combination of an electromagnet type or stripline type and a permanent magnet that supplies only a fixed magnetic field may be used. The magnetic field application mechanism 114 can induce spin torque resonance by applying a magnetic field to the magnetoresistive effect element 106, and further adjust the spin torque resonance frequency by changing the applied magnetic field. Can do. That is, the magnetic field application mechanism 114 has a function as a frequency control means for spin torque resonance.

  Here, the spin torque resonance phenomenon (ferromagnetic resonance phenomenon) generated in the magnetoresistive effect element 106 due to the influence of the high frequency signal will be described.

  When a magnetic field is applied to the magnetoresistive effect element 106 and at the same time a high frequency signal having the same frequency as the intrinsic spin torque resonance frequency (ferromagnetic resonance frequency) is input to the magnetoresistive effect element 106, the magnetization of the magnetization free layer 109 becomes spin torque resonance. Vibrates at frequency. This phenomenon is called a spin torque resonance phenomenon. The element resistance value of the magnetoresistive effect element 106 is determined by the relative angle of magnetization between the magnetization fixed layer 108 and the magnetization free layer 109. Therefore, the resistance value of the magnetoresistive effect element 106 at the time of spin torque resonance periodically changes with the vibration of magnetization of the magnetization free layer 109. That is, the magnetoresistive effect element 106 can be handled as a resistance vibration element whose resistance value periodically changes at the spin torque resonance frequency. Furthermore, when a high frequency signal having the same frequency as the spin torque resonance frequency is input to the resistance vibration element, the respective phases are synchronized, and the impedance to the high frequency signal is reduced. That is, the magnetoresistive effect element 106 can be handled as a resistance element that reduces the impedance of the high-frequency signal at the spin torque resonance frequency due to the spin torque resonance phenomenon. Further, as the magnetic field applied to the magnetoresistive element 106 becomes stronger, the spin torque resonance frequency becomes higher.

  Further, when a direct current is applied to the magnetoresistive effect element 106 at the time of spin torque resonance, the spin torque is increased and the amplitude of the oscillating resistance value is increased. As the amplitude of the oscillating resistance value increases, the amount of change in the element impedance of the magnetoresistive effect element 106 increases. Further, as the current density of the applied direct current increases, the spin torque resonance frequency decreases. Therefore, the spin torque resonance frequency of the magnetoresistive effect element 106 can be controlled by adjusting the magnetic field from the magnetic field application mechanism 114 or adjusting the applied DC current from the DC application terminal 107.

  Due to the spin torque resonance phenomenon, the frequency components that coincide with the spin torque resonance frequency of the magnetoresistive effect element 106 in the high frequency components of the high frequency signal input from the first port 101 are low impedance. Since it passes through the magnetoresistive effect element 106 in the state and flows to the ground 115, it is difficult to output to the second port 102. That is, the magnetoresistive effect device 100 has a function of a high frequency filter in which a frequency band near the spin torque resonance frequency is a cutoff band.

  In FIG. 2A, currents (differential mode currents) of the same magnitude and in opposite directions flow through the substantially parallel first signal line 104 and second signal line 105 constituting the differential transmission line 103. It is a figure explaining the magnetic field applied to the magnetoresistive effect element 106 in the case of being. Here, it is assumed that a high-frequency current flows through the first signal line 104 from the front to the back and through the second signal line 105 from the back to the front.

At this time, as shown in FIG. 2A, the magnetic field H ₁ generated by the high-frequency current flowing in the first signal line 104 (indicated by a solid arrow) is from the front side with the first signal line 104 as the central axis. Concentric lines of magnetic force are formed in the clockwise direction as viewed. On the other hand, the magnetic field H ₂ generated by the high-frequency current flowing in the second signal line 105 (indicated by a dashed arrow) is concentric in the counterclockwise direction when viewed from the front side with the second signal line 105 as the central axis. Magnetic field lines are formed on the surface. The magnetic fields H ₁ and H ₂ become smaller as the distance from the central axis increases.

In FIG. 2A, the magnetic fields H ₁ and H ₂ generated at the respective positions surrounded by the alternate long and short dash line are synthesized and shown as a synthesized magnetic field H ₃ (indicated by a thick solid arrow) in FIG.

  In FIG. 3A, currents (common mode currents) having the same magnitude and the same direction flow through the substantially parallel first signal line 104 and second signal line 105 constituting the differential transmission line 103. It is a figure explaining the magnetic field applied to the magnetoresistive effect element 106 in the case of being. Here, it is assumed that a high-frequency current flows through the first signal lines 104 and 105 from the front toward the back.

At this time, as shown in FIG. 3A, the magnetic field H ₄ (indicated by a solid arrow) generated by the high-frequency current flowing in the first signal line 104 is from the front side with the first signal line 104 as the central axis. Concentric lines of magnetic force are formed in the clockwise direction as viewed. In addition, the magnetic field H ₅ (indicated by a dashed arrow) generated by the high-frequency current flowing in the second signal line 105 is concentric with the second signal line 105 as the central axis in the clockwise direction when viewed from the front side. Form magnetic field lines. The magnetic fields H ₄ and H ₅ become smaller as the distance from the central axis increases.

In FIG. 3A, the magnetic fields H ₄ and H ₅ generated at the respective positions surrounded by the alternate long and short dash line are synthesized and shown as a synthesized magnetic field H ₆ (indicated by a thick solid arrow) in FIG.

  FIG. 4 shows the magnetoresistive effect element 106 when the differential mode current and the common mode current flow through the substantially parallel first signal line 104 and second signal line 105 constituting the differential transmission line 103. It is a figure explaining the applied magnetic field. The magnetoresistive effect element 106 is arranged so that the stacking direction L is substantially perpendicular to the plane P including the first signal line 104 and the second signal line 105.

As shown in FIG. 2B, the synthetic magnetic field H ₃ generated by the differential mode current (indicated by a solid arrow) forms magnetic lines of force around the first signal line 104 in the clockwise direction. Magnetic field lines are formed around the second signal line 105 in a counterclockwise direction.

On the other hand, the synthetic magnetic field H ₆ generated by the common mode current (indicated by a dashed arrow) is centered on the first signal line 104 and the second signal line 105 as shown in FIG. Magnetic field lines are formed around it in a clockwise direction.

The magnitudes and directions of the magnetic fields H ₃ and H ₆ applied to the magnetoresistive effect element 106 are determined by the relative positional relationship between the first signal line 104 and the second signal line 105. When the magnetoresistive effect element 106 is on the plane P ₁ (a position intersecting the plane P ₁ ), the magnetoresistive effect element 106 receives the respective magnetic fields generated by the differential mode current and the common mode current in the plane P 1. ₁ is applied in a direction substantially perpendicular to ₁ .

Furthermore, in the region R sandwiched between the first signal line 104 and the second signal line 105 on the plane P ₁ , the direction of the magnetic field generated around the first signal line 104 due to the flow of the common mode current The direction of the magnetic field generated around the second signal line 105 is almost opposite. Therefore, the synthetic magnetic field by the common mode current in this region R becomes a value close to zero. Therefore, when the magnetoresistive effect element 106 is arranged in the region R, only the magnetic field due to the differential mode current is applied to the magnetoresistive effect element 106.

If the magnetoresistance effect element 106 is disposed on one side of the plane P _1, the magnetic field applied to the magneto-resistance effect element 106 by the common mode current, it includes a component parallel to the plane P _1. The magnetic field of the component parallel to the plane P ₁ due to the common mode current is applied to the first signal line 104 and the second signal line 105 in a position overlapping the region R, that is, in a plan view from the stacking direction L of the magnetoresistance effect element 106. A large value is indicated at the sandwiched position.

Further, in the region R, an intermediate point (intermediate line) R ₁ between the first signal line 104 and the second signal line 105 is on a plane P ₂ (a position intersecting with the plane P ₂ ) substantially orthogonal to the plane P _1. When there is the magnetoresistive effect element 106, the magnetic field shows a larger value. In addition, the magnetic field has a particularly large value in a predetermined region separated from the intermediate point R _{1 in} a direction perpendicular to the plane P ₁ .

The differential mode currents, among the magnetic field applied to the magnetoresistive element 106, the component perpendicular to the plane P ₁ indicates a large value on a plane P _2, decreases with increasing distance from the plane P _2.

As described above, in the magnetoresistive effect device 100 according to the present embodiment, the magnetoresistive effect is provided on one side of the plane P ₁ including the first signal line 104 and the second signal line 105 constituting the differential transmission line 103. element 106 is arranged, the lamination surface is parallel with the plane P _1.

  Therefore, when a differential mode current flows through the first signal line 104 and the second signal line 105, a magnetic field perpendicular to the laminated surface is applied to the magnetoresistive effect element 106. The magnetization of the magnetization free layer 109 undergoes precession about the direction of the applied magnetic field and the frequency of the differential mode current is close to the resonance frequency of the magnetoresistive effect element 106. Resonates with. Thereby, the impedance of the magnetoresistive effect element 106 with respect to the differential mode current is lowered.

  On the other hand, when a common mode current flows through the first signal line 104 and the second signal line 105, a magnetic field parallel to the laminated surface is applied to the magnetoresistive effect element 106. In this case, the magnetization of the magnetization free layer 109 hardly resonates with the magnetization of the magnetization free layer 109 perpendicular to the laminated surface even if precession about the direction of the applied magnetic field is performed. Therefore, the impedance of the magnetoresistive effect element 106 does not decrease.

  Therefore, in the magnetoresistive effect device 100 according to the present embodiment, only the differential mode current among the currents flowing through the differential transmission line 103 can be passed to the magnetoresistive effect element 106 side. As a result, the differential transmission line It becomes possible to reduce the differential mode current flowing through the transistor 103. That is, the magnetoresistive effect device 100 of this embodiment has a function as a filter that selectively cuts off a differential mode current in the vicinity of a predetermined frequency (resonance frequency).

  According to the magnetoresistive effect device 100 of the present embodiment, since the differential mode current can be temporarily interrupted, in order to take measures to reduce the common mode current, the current state of the common mode current in a specific signal line is determined. It is possible to grasp quantitatively whether or not it flows to a certain extent.

In operating the magnetoresistive effect device 100 according to the present embodiment, among the current flowing through the magnetoresistive effect element (filter element) 106, the ratio of the differential mode current is increased and the ratio of the common mode current is decreased. Is preferred. From such a point of view, it is preferable to apply as much of the magnetic field by the differential mode current as possible perpendicular to the laminated surface so that ferromagnetic resonance is likely to occur. Further, it is preferable to apply as much of the magnetic field by the common mode current as possible in parallel to the laminated surface so that ferromagnetic resonance does not easily occur. Therefore, specifically, the magnetoresistive effect element 106 is preferably disposed at a position overlapping the region R sandwiched between the first signal line 104 and the second signal line 105, and the first portion of the region R is It is arranged at a midpoint R ₁ and position overlapping the signal line 104 and the second signal line 105, more preferred.

  That is, in plan view from the stacking direction L, one or both of the magnetoresistive effect element 106 connected to the first signal line 104 and the magnetoresistive effect element 106 connected to the second signal line is the first signal. It is more preferable that the distance from the line 104 and the distance from the second signal line 105 are equal. In this case, the difference between the cutoff characteristics in the vicinity of the resonance frequency of each magnetoresistive effect element with respect to the common mode current flowing in the first signal line and the cutoff characteristics with respect to the differential mode current is the largest, compared with the common mode current. Thus, more differential mode current can be cut off.

  The number of magnetoresistive effect elements 106 connected to each of the first signal line 104 and the second signal line 105 may be one or plural. In addition, the number, shape, size, and the like of the magnetoresistive effect elements 106 to be connected may not be the same for the first signal line 104 and the second signal line 105. However, in order to stabilize the operation as a differential transmission line, it is necessary to align the electrical characteristics of the first signal line 104 and the second signal line 105. For the number, shape, size, etc. It is assumed that the combined impedance is adjusted.

  Modifications 1 and 2 when a plurality of magnetoresistive elements 106 are connected to the first signal line 104 and the second signal line 105 are shown in FIGS.

  FIG. 5 is a perspective view of a magnetoresistive effect device 150 according to the first modification. In the magnetoresistive effect device 110, a plurality of magnetoresistive effect elements having different ferromagnetic resonance frequencies of the magnetization of the magnetization free layer are connected in parallel to each of the first signal line 104 and the second signal line 105. . About another structure, it is the same as that of the structure of the said embodiment, About the same location as the said embodiment, it has shown with the same code | symbol irrespective of the difference in shape.

  FIG. 6 is a perspective view of a magnetoresistive effect device 160 according to the second modification. In the magnetoresistive effect device 120, a plurality of magnetoresistive effect elements having different ferromagnetic resonance frequencies of magnetization of the magnetization free layer are connected in series to each of the first signal line 104 and the second signal line 105. . About another structure, it is the same as that of the structure of the said embodiment, About the same location as the said embodiment, it has shown with the same code | symbol irrespective of the difference in shape.

  As in Modifications 1 and 2, by connecting a plurality of magnetoresistive elements having different resonance frequencies to each signal line, the types of frequencies of common mode currents that can be filtered are increased, and the cutoff frequency band is reduced. Can be set widely.

<Second embodiment>
FIG. 7 is a perspective view of a magnetoresistive effect device 200 according to the second embodiment of the present invention. The magnetoresistive effect device 200 is different from the magnetoresistive effect device 100 of the first embodiment in the relationship between the plane P ₁ including the first signal line 104 and the second signal line 105 and the stacking direction L of the magnetoresistive effect element 106. Different. That is, the lamination direction L of the magnetoresistive effect element 106 is perpendicular to the plane P ₁ including the first signal line 104 and the second signal line 105 in the _first embodiment, but is parallel to the present embodiment. It has become. About another structure, it is the same as that of the structure of 1st embodiment, About the same location as 1st embodiment, it has shown with the same code | symbol irrespective of the difference in shape. Also in this embodiment, the same effect as the first embodiment can be obtained.

FIG. 8 shows the magnetoresistive effect element 106 when the differential mode current and the common mode current flow through the substantially parallel first signal line 104 and second signal line 105 constituting the differential transmission line 103. It is a figure explaining the applied magnetic field. The magnetoresistive effect element 106 is arranged so that the stacking direction L thereof is substantially perpendicular to the plane P ₁ including the first signal line 104 and the second signal line 105.

The direction of the magnetic field generated around the first signal line 104 and the second signal line 105 is the same as in the first embodiment. Therefore, if the magnetization direction of the magnetization fixed layer 108 parallel to the plane P _1, a preferred arrangement of the magnetoresistive element 106 is also similar to the first embodiment. Specifically, it is necessary that they are disposed on one side of the plane P _1, preferably disposed in a position overlapping with the region R, and more preferably if further disposed on the plane P ₂ .

<Third embodiment>
FIG. 9 is a perspective view of a magnetoresistive effect device 300 according to the third embodiment of the present invention. The magnetoresistive effect device 300 also includes the magnetoresistive effect device 100 according to the first embodiment in the relationship between the plane P ₁ including the first signal line 104 and the second signal line 105 and the stacking direction L of the magnetoresistive effect element 106. Different. That is, the lamination direction L of the magnetoresistive effect element 106 is perpendicular to the plane P1 including the first signal line 104 and the second signal line 105 in the _first embodiment, but obliquely in the present embodiment. Crossed. About another structure, it is the same as that of the structure of 1st embodiment, About the same location as 1st embodiment, it has shown with the same code | symbol irrespective of the difference in shape. Also in this embodiment, the same effect as the first embodiment can be obtained.

FIG. 10 shows the magnetoresistive effect element 106 when the differential mode current and the common mode current flow through the substantially parallel first signal line 104 and second signal line 105 constituting the differential transmission line 103. It is a figure explaining the applied magnetic field. The magnetoresistive effect element 106 is arranged so that the stacking direction L obliquely intersects the plane P ₁ including the first signal line 104 and the second signal line 105.

The direction of the magnetic field generated around the first signal line 104 and the second signal line 105 is the same as in the first embodiment. Therefore, if the magnetization direction of the magnetization fixed layer 108 parallel to the plane P _1, a preferred arrangement of the magnetoresistive element 106 is also similar to the first embodiment. Specifically, it is necessary that they are disposed on one side of the plane P _1, preferably disposed in a position overlapping with the region R, and more preferably if further disposed on the plane P ₂ .

100, 150, 160, 200, 300 ... magnetoresistive effect device 101 ... first port 102 ... second port 103 ... differential transmission line 104 ... first signal line 105 ... Second signal line 106 ... magnetoresistive effect element 107 ... DC application terminal 108 ... magnetization fixed layer 109 ... magnetization free layer 110 ... spacer layer 111 ... upper electrode 112 ... lower part Electrode 113 ... Power source 114 ... Magnetic field application mechanism 115 ... Ground H _{1 to} H ₆ ... Magnetic field L ... Stacking direction P ₁ , P ₂ ... Plane R ... Region R ₁ · ..Intermediate point

Claims (10)

A first port for inputting a high-frequency signal;
A second port for outputting a high-frequency signal;
A first signal line and a second signal line that connect the first port and the second port to form a differential transmission line;
A magnetoresistive effect element connected to each of the first signal line and the second signal line;
A DC application terminal connected to the first signal line and the second signal line,
The magnetoresistive effect element includes a magnetization fixed layer, a magnetization free layer, and a spacer layer sandwiched between the magnetization fixed layer and the magnetization free layer on a plane including the first signal line and the second signal line, respectively. Vertically stacked,
The magnetoresistive effect element is arranged so as to be sandwiched between the first signal line and the second signal line in a plan view from the stacking direction;
A magnetoresistive effect device, wherein an easy axis of magnetization of the magnetization fixed layer is perpendicular to a laminated surface of the magnetoresistive effect element. A first port for inputting a high-frequency signal;
A second port for outputting a high-frequency signal;
A first signal line and a second signal line that connect the first port and the second port to form a differential transmission line;
A magnetoresistive effect element connected to each of the first signal line and the second signal line;
A DC application terminal connected to the first signal line and the second signal line,
The magnetoresistive effect element is formed by laminating a magnetization fixed layer, a magnetization free layer, and a spacer layer sandwiched between the magnetization fixed layer and the magnetization free layer,
The magnetoresistive element is arranged such that the magnetization of the magnetization free layer is ferromagnetically resonated by a magnetic field in a direction perpendicular to a plane including the first signal line and the second signal line. Magnetoresistive device.   3. The magnetoresistive effect according to claim 2, wherein the magnetoresistive effect element is disposed so as to be sandwiched between the first signal line and the second signal line in a plan view from the stacking direction. device.   In the plan view from the stacking direction, the magnetoresistive effect element connected to the first signal line is disposed so that the distance from the first signal line and the distance from the second signal line are equal. The magnetoresistive effect device according to claim 3, wherein   In the plan view from the stacking direction, the magnetoresistive effect element connected to the second signal line is disposed so that the distance from the first signal line and the distance from the second signal line are equal. The magnetoresistive effect device according to claim 3, wherein the magnetoresistive effect device is provided.   The magnetoresistive effect device according to claim 1, further comprising a frequency control unit that controls a ferromagnetic resonance frequency of magnetization of the magnetization free layer.   The plurality of magnetoresistive elements having different ferromagnetic resonance frequencies of magnetization of the magnetization free layer are connected in parallel to the first signal line. The magnetoresistive effect device according to one item.   The plurality of magnetoresistive elements having different ferromagnetic resonance frequencies of magnetization of the magnetization free layer are connected in parallel to the second signal line. The magnetoresistive effect device according to one item.   The plurality of magnetoresistive elements having different ferromagnetic resonance frequencies of magnetization of the magnetization free layer are connected in series to the first signal line. The magnetoresistive effect device according to one item.   10. The plurality of magnetoresistive elements having different ferromagnetic resonance frequencies of magnetization of the magnetization free layer are connected in series to the second signal line. The magnetoresistive effect device according to any one of the above.

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