WO2007015475A1 - Magnetic energy/electric energy conversion element having nano-structure - Google Patents

Abstract

There is provided a magnetic energy/electric energy conversion element having nano-structure for converting electric energy into magnetic energy to be accumulated and extracting the accumulated magnetic energy as electric energy when required. The conversion element has a nanowire formed by electron-conductive magnetic body. The nanowire includes a first region (2) having a wide wire width, a second region (3) having a wire width restricted in a wedge form at the portion continuous to the first region (2), a third region (4) having a wire width gradually reduced toward the second region (3), and a fourth region (5) having a wide wire width at the portion continuous to the third region (4). The nanowire has a first electrode (11) in the first region, a central electrode (12) at the top end of restricted portion of the second region of the third region side, and a second electrode (13) in the fourth region. Input voltage is applied across the first electrode (11) and the second electrode (13) and amplified output voltage is extracted from between the central electrode (12) and the second electrode (13).

Description

 Specification

 Magnetic and electrical energy interconversion device with nanostructures

 Technical field

 [0001] The present invention relates to a magnetic and electrical energy mutual conversion element having a nanostructure that mutually converts magnetic energy into electrical energy and electrical energy into magnetic energy.

 Background art

 [0002] Electrons have charge and spin as their primary attributes. The power of conventional electronics that exclusively uses the charge of electrons In recent years, development of devices using spin, which is another attribute of electrons, has been active. For example, mouth devices using electron spin, giant magnetoresistive (GMR) elements and magnetic tunnel (TMR) elements that control electrical resistance by electron spin have been fabricated (Non-Patent Document 1, 2).

 [0003] By the way, in magnetic materials, it is known that conversion of magnetic energy and electrical energy is possible as a consequence of the conservation of angular motion between the spin current of electrons and the localized spin of the magnetic material (non- (See Patent Documents 3 and 4). The principle will be described below.

 Figure 6 shows the domain wall and the domain wall movement in the electron-conductive ferromagnetic wire. (A) shows the position of the domain wall before passing the current through the wire, and (b) shows the current added for Δt time. The position of the domain wall is shown. It is assumed that the magnetization is uniformly magnetized in the axial direction (z direction) of the fine wire, and A is the cross-sectional area of the fine magnetic wire.

 When a current having a current density j is passed through a magnetic wire, the spin of the conduction electron (size 1Z2) that carries the current tends to be parallel to the direction of the localized spin M (size S) due to the ferromagnetic interaction. The conduction electrons that carry the current form a spin-polarized spin current. If the polarizability is p, the spin current j (density) is expressed by the following equation (1).

[Number 1] ( ¹⁾

 Here, the unit of charge of electrons is e.

Next, as shown in FIG. 6 (a), the localized spin M of the magnetic material is reversed and the domain wall W is formed. Think if you are. The arrow of the localized spin M indicates the direction of the magnetic field due to the localized spin M. As a result of the conservation of angular momentum between the spin of the conduction electron and the localized spin of the domain wall W, the spin current j that flows into the domain wall W per unit time is equal to the amount of change in the localized spin of the domain wall W. Since the localized spin amount of the domain wall W is conserved, the domain wall W moves in the same direction as the electron flow (the direction opposite to the current) at the speed given by the following equation (2).

[Equation 2]

pv _c

 V:

Where V is the volume of the unit cell (= a ³ , a is the interatomic distance).

 As shown in Fig. 6 (a), the external magnetic field B is applied parallel to the thin line, and the change in magnetic energy when the domain wall W is moved under the magnetic field B is evaluated. When the domain wall moves at the speed of equation (2) during time At, the direction of v A tA / v localized spins changes from the direction opposite to the direction of magnetic field B to the direction of magnetic field B. Therefore, the magnetic energy is reduced by the following formula (3).

[Equation 3]

AE = 2SgM _B BvMA / v _c (3) where g is g_factor and μ is Bohr magneton. This corresponds to a decrease in magnetic energy.

 Β

Since the energy is dissipated by the current, the following equation (4) holds.

Picture

ΑΕ = VjAAt (4) where V is the potential difference generated at both ends of the thin wire. By combining Eqs. (2) and (3) into Eq. (4), the following Eq. (5) is obtained.

[Equation 5]

 e

Equation (5) is the relationship between magnetic energy E (= _gj u B) and electrical energy E (= _e V).

 magnetic B electnc

Showing the staff. That is, if the domain wall W moves by passing a current through a thin wire of uniform width to which the external magnetic field B is applied, the magnetic energy based on the external magnetic field B is It shows that it can be converted into energy, and in fact, has been quantitatively verified (see Non-Patent Document 4). In addition, the conversion formula between magnetic energy and electric energy is expressed by the following formula (6).

 [Equation 6]

tb hjelectric

tb

[0006] Non-Patent Document 1: Maekawa Keisuke: Solid State Physics No. 32, No. 4, p. 3 (April 15, 1997, issued by Agne Technology Center)

 Non-Patent Document 2: Research Report on Spin Electronics Research II (March 1999, published by Japan Electronics Industry Promotion Association)

 Non-Patent Document 3: A. Yamaguchi et al: Phs. Rev. Lett. 92, 077205 (2004)

 Non-Patent Document 4: J.Z.Sun et al .: FA-11, 49th MMM (2004)

 Disclosure of the invention

 Problems to be solved by the invention

[0007] The principle of conversion between magnetic energy and electric energy described above is simply an external magnetic field.

It only shows that magnetic energy based on B can be converted into electrical energy, and this alone has the problem that it is not a useful element that can be used in industry.

In view of the above problems, an object of the present invention is to provide a magnetic and electrical energy mutual conversion element having a nanostructure.

 Means for solving the problem

[0009] The inventors of the present invention can convert electric energy into magnetic energy and store it by making the magnetic energy that can be taken by the domain wall different depending on the position of the nanostructure such as a thin wire. The inventors have conceived of an interconversion element of magnetic and electric energy having a nanostructure that can take out magnetic energy as electric energy when necessary, and have reached the present invention.

[0010] In order to achieve the above object, a magnetic and electrical energy mutual conversion element having a nanostructure of the present invention has a nanostructure made of a magnetic body having electron conductivity, and both ends of the nanostructure. Connected to the center of the nanostructure and the first and second electrodes connected to the A first domain wall holder that can hold a domain wall between the first electrode and the center electrode of the nanostructure, and a domain wall between the second electrode and the center electrode of the nanostructure. A second domain wall holder that can be formed, wherein the magnetic energy of the first domain wall holder and the second domain wall holder is smaller than the magnetic energy of both ends of the nanostructure. The magnetic energy is configured to be larger than the magnetic energy of the second domain wall holder, and electrical energy is applied between the first electrode and the central electrode via an input voltage or current, and the central electrode and the second electrode The output electric energy amplified through the output voltage or current is taken out from between.

 In the above configuration, the magnetic energy is preferably stored by applying a voltage or current having a polarity opposite to the input voltage or current between the first electrode and the center electrode between the first electrode and the second electrode.

 [0011] According to the above configuration, the domain wall existing in the first domain wall holder is moved to the second domain wall holder by applying electric energy between the first electrode and the center electrode via an input voltage or current. As a result, the domain wall moves, and the magnetic energy corresponding to the decrease in magnetic energy caused by the domain wall movement is converted into electric energy, and this electric energy is output from the central electrode and the second electrode to the output voltage or current. Can be taken out. To store magnetic energy, the corresponding electrical energy is applied to the first electrode and the second electrode via voltage or current, and the domain wall held in the second domain wall holder is held again in the first domain wall. It can be done by returning to the department.

 [0012] In the above configuration, the nanostructure preferably includes a first region in which the width of the thin line is wide, a second region in which the width of the thin line continuous to the first region is constricted in a wedge shape, and the second region. It consists of a third region where the width of the thin line continuing to the region 2 gradually narrows and a fourth region where the width of the thin line continuing to the third region is wide, and the width of the first region is d The narrowest width of the second region

 1

 D, the widest width of the third region is d, the narrowest width is d, and the fourth region

2 3 3m

 Where d> d> d> d and d> d.

4 1 3 2 3m 4 3m

 The first electrode is provided in the first region, the center electrode is provided on the second region side of the third region, and the second electrode is provided in the fourth region.

[0013] In the above configuration, the magnetic energy of the domain wall is proportional to the width of the thin wire, The domain wall in the second region generates a magnetic energy proportional to d-d and the first electrode and the central electrode.

 3 2

 Move to the third region by receiving via the input voltage or current applied between the poles. The magnetic energy that can be taken by the domain wall gradually decreases because the width of the third region gradually decreases, so that the magnetic wall that has moved to the third region spontaneously moves in the direction of narrowing and the extra magnetic energy. Is dissipated as electrical energy and passed to the current. This excess electrical energy can be extracted as electrical energy from the center electrode and the second electrode via the output voltage or current. The total amount of excess electrical energy is d — d

 3 Proportional to 3m and d> d> d, that is, d — d> d — d.

 3 2 3m 3 3m 3 2

 Output electric energy larger than the input electric energy required to move the domain wall in the region to the third region can be obtained. For example, when used as a voltage amplification element, it operates as a voltage amplification element having a single energy gain. . The mutual conversion element of magnetic and electric energy having a nanostructure composed of fine wires can be configured as a planar structure on a substrate.

 [0014] In the above configuration, the nanostructure preferably has a lamination structure force, and both end portions and the central portion are wide. The first narrow portion that can hold the domain wall between each end portion and the central portion is narrow. And the 2nd domain wall holding part is formed. The material of the nanostructure is preferably any of permalloy, iron, iron-cobalt alloy, iron-platinum alloy, and samarium-conoleto alloy. By making the nanostructure a laminated structure, the thickness in the stacking direction can be made smaller than that of a planar nanostructure, so that the internal resistance of the magnetic and electrical energy conversion element having the nanostructure is reduced. be able to. It is also advantageous for increasing the integration density.

[0015] In the above configuration, preferably, the nanostructure includes the first hard magnetic layer, the first soft magnetic layer, the second hard magnetic layer, the second soft magnetic layer, and the ^third hard magnetic layer. The first electrode is connected to the first hard magnetic layer, which is one end of the nanostructure, and the third hard, which is the other end of the nanostructure. The second electrode is connected to the magnetic layer, the central electrode is connected to the second hard magnetic layer, and the first soft magnetic layer and the ^second soft magnetic layer serve as a domain wall holding portion that holds the domain wall. .

In the above configuration, preferably, the hard magnetic layer is made of iron-platinum alloy, and the soft magnetic layer Consists of permalloy.

 According to the above configuration, since it is only necessary to form the nanostructure with a uniform width in the vertical direction without the need to form a narrow region for forming the domain wall holding portion in the nanostructure, the manufacture is facilitated. For this reason, the length L in the vertical direction of the nanostructure can be made smaller than that of the planar nanostructure, so that the internal resistance of the magnetic and electrical energy conversion element having the nanostructure can be reduced. it can. Moreover, it is advantageous also for the integration.

In the present invention, when magnetic and electrical energy mutual conversion elements having nanostructures are arranged in a matrix, the magnetic and electrical energy mutual conversion elements having nanostructures are integrated. You can do it.

 The invention's effect

 [0017] According to the present invention, by passing an electric current through a nanostructure, for example, an extraction electrode provided on a magnetic wire, electric energy is converted into magnetic energy and stored, and the stored magnetic energy is converted into electric energy. It can be converted into a single energy source and taken out. Conventional devices that convert electrical energy into magnetic energy and store it, and convert the stored magnetic energy into electrical energy and extract it are composed of, for example, a ferromagnetic material and a coil wound around the ferromagnetic material. Since the interaction between the magnetization of the magnetic material and the current flowing through the coil requires a large and bulky coil, the magnetic and electrical energy conversion device having the nanostructure of the present invention is It is possible to reduce the size and integration, and to increase the energy efficiency.

 Brief Description of Drawings

 [0018] FIG. 1 shows a configuration of a magnetic and electrical energy mutual conversion element having a nanostructure according to a first embodiment of the present invention, where (a) shows an initial state and (b) shows an input voltage. (C) is a diagram showing the width of each portion of the thin line.

 FIG. 2 is a diagram showing the relationship between the domain wall energy and the domain wall energy of the magnetic / electrical energy mutual conversion element having the nanostructure of the present invention, where the vertical axis is the domain wall energy, and the horizontal axis is the location of the domain wall. Indicates.

FIG. 3 schematically shows a magnetic and electrical energy interconversion element having a nanostructure according to a second embodiment of the present invention, in which (A) is a cross-sectional view and (B) is a plan view. . FIG. 4 schematically shows the structure of a magnetic and electrical energy mutual conversion element having a nanostructure according to a third embodiment of the present invention, where (A) is a cross-sectional view and (B) is a plan view. Is

FIG. 5 is a perspective view schematically showing a configuration of an integrated circuit using a magnetic and electrical energy mutual conversion element having a nanostructure of the present invention.

 [Fig. 6] Domain wall and domain wall movement in an electron-conducting ferromagnetic wire. (A) shows the position of the domain wall before passing a current through the magnetic wire, and (b) shows the current after adding the At time. The position of the domain wall is shown.

Explanation of symbols

1, 20, 30: Magnetic and electrical energy interconversion elements with nanostructures

2: First region with a wide thin line

3: The second area where the width of the thin line is wedged

4: Third area where the width of the thin line gradually decreases

5: The width of the thin line is wide, the fourth area

6: Domain wall

 7: Arrow indicating the direction of localized spin

 8, 23A: 1st domain wall holder

 9, 24A: Second domain wall holder

11, 26, 40: 1st electrode

 12, 28, 42: Center electrode

 13, 27, 41: Second electrode

22: Wide first layer

23: Second layer

 24: 3rd layer

 25: Fourth layer

 34: First hard magnetic layer

 35: First soft magnetic layer

36: Second hard magnetic layer 37: Second soft magnetic layer

 38: Third hard magnetic layer

 26A, 27A, 28A, 44, 45, 46, 52, 54, 56: Electrode wiring

 50: Integrated circuit using magnetic and electrical energy conversion elements with nanostructures

 BEST MODE FOR CARRYING OUT THE INVENTION

[0020] Hereinafter, some of the best modes for carrying out the present invention will be described in detail with reference to the drawings.

 FIG. 1 shows a configuration of a magnetic and electrical energy mutual conversion element having a nanostructure according to the first embodiment of the present invention, where (a) shows an initial state, and (b) shows an input voltage. (C) is a diagram showing the width of each part of the thin line.

 The magnetic / electrical energy mutual conversion element 1 having the nanostructure of the present invention has a nanostructure force that has electron conductivity and magnetic thin wire force. A magnetic thin wire, that is, a magnetic thin wire (hereinafter referred to as a thin wire as appropriate) is continuous with the first region 2 where the thin wire is wide and the first region 2 as shown in FIG. 1 (a). The second region 3 in which the width of the thin line is wedged, the third region 4 in which the width of the thin line continuing to the second region 3 is gradually narrowed, and the thin line continuing in the third region 4 And the fourth region 5 is wide.

[0021] As shown in FIG. 1 (c), the width of each part of the thin line is such that the width of the first region 2 is d and the width of the second region 3 is

 1

 D is the narrowest width, d is the widest width of the third region 4 and d is the thinnest width.

 2 3 3m

 If the width of region 5 is d, the relation d> d> d> d and d> d

 4 1 3M 2 3m 4 3m

 It is configured.

 In addition, a first electrode 11 is provided in the first region 2, a center electrode 12 is provided on the second region 3 side of the third region 4, and a second electrode 13 is provided in the fourth region 5. Further, as shown in FIG. 1 (a), each part of the thin line is magnetized as indicated by an arrow 7 to form a domain wall 6 in the region 3. As will be described later, the domain wall has the narrowest width (d) of the second region 3 or the narrowest width (d) of the third region 4.

 13

). Regarding the domain wall retention, the area of the narrowest width of the second area 3 is m.

The first domain wall holder 8 is referred to as the narrowest region of the third region 4 and is referred to as the second domain wall holder 9. [0023] The width and thickness of the magnetic wire of the present invention are indispensable to be nanometer size. That is, when the width and film thickness of the magnetic wire are 1 μm or more, the domain wall is not driven uniformly by the current, and the structure of the domain wall itself changes (see Non-Patent Document 3).

 [0024] Here, as the material of the magnetic wire, permalloy, iron, an alloy composed of iron and cobalt (hereinafter referred to as an iron-cobalt alloy as appropriate), an alloy composed of iron and platinum (hereinafter referred to as iron as appropriate). It is possible to use a metal alloy (referred to as a samarium-cobalt alloy as appropriate), which is also called samarium-cobalt alloy.

 Next, the operation of the magnetic and electrical energy mutual conversion element having the nanostructure of the present invention will be described.

 FIG. 2 is a diagram showing the relationship between the position of the domain wall and the domain wall energy of the magnetic and electrical energy mutual conversion element having the nanostructure of the present invention, where the vertical axis represents the domain wall energy, and the horizontal axis represents the location of the domain wall. Show. The domain wall position “1” is the first domain wall holder 8 corresponding to the position where the thin line width of the second region 3 in FIG. 1 is the narrowest. The domain wall position “0” is the second domain wall holder 9 corresponding to the boundary position between the third region 4 and the fourth region 5 in FIG. E indicates the difference in domain wall energy when the domain wall 6 a is present at the position of “0” when the domain wall 6 a is present at the position indicated by “1”, and E is the position of the domain wall 6 in the vicinity of the central electrode 12. When present in b

 This shows the difference in domain wall energy when the domain wall energy exists at the position of '1'.

The energy of the domain wall in each part of the magnetic wire shown in FIG. 1 (a) will be described. The magnitude of the exchange interaction of the magnetic material is A (unit CiZm), and the uniaxial magnetic anisotropy constant is K (unit CFZ

 ex u

m ³ ]), the energy σ (unit [j / m]) of the domain wall 6 per unit cross-sectional area is given by equation (7).

[Equation 7]

 Therefore, the energy stored in the domain wall 6 is obtained by multiplying Equation (7) by the cross-sectional area of the thin line. In the thin line in Fig. 1 (a), assuming that the cross-sectional areas of the thin lines at the positions indicated by "0", "1" and the central electrode 12 are A, A and A, respectively, the energy barriers E and E shown in Fig. 2

 0 1 b a b is given by the following equation (8).

[Equation 8] Ea = a _w (Ai-Ao), Eb = a _w (Ab-Αι) (8) Here, if the thin film thickness is h and the width of each part shown in Fig. 1 (c) is used, A = d X h,

 0 3m

A = d X h, A = d X h, and since d> d> d, A> A> A,

1 2 b 3 3 2 3m b 1 0 As shown in Fig. 2, E> E can be satisfied. Since d> d, the first electrode 1 a b 1 3

 When electric energy is supplied via 1 and the central electrode 12, the domain wall 6 in the second region 3 is excited toward the third region 4 side. Since d> d, move the third area 4

 4 3m

The domain wall 6 to be stopped stops at the position "0".

 In the state of Fig. 1 (a), that is, when the domain wall 6 is at the position of "1" in Fig. 2, by applying a voltage or current pulse between the first electrode 11 and the central electrode 12, the equation (2 ), The domain wall 6 has a finite velocity, moves over the energy barrier E shown in Fig. 2 and moves to the position of the center electrode 12 b

Move. As a result, the domain wall 6 moves from the first domain wall holder 8 to the second domain wall holder 9. At this time, work E is performed on the domain wall 6 by an external power source.

 b

、て散逸する。 In the third region 4, the width of the thin line is narrow and has a gradient, and the domain wall energy that the domain wall can take decreases according to the gradient. Therefore, the domain wall 6 has a gradient of the domain wall energy in the third region 4. According to the following equation (5) and (6): It is transferred to the conduction electrons and finally the central electrode 12 and the second electrode 13

, Dissipate.

 In other words, the input electrical energy E applied between the first electrode 11 and the central electrode 12 is taken out, and b (E + E) is extracted as the output electrical energy between the second electrode 13 and the central electrode 12. ab

It is. When the energy amplification factor at this time is G, the amplification factor G is expressed by the following equation (9) using equation (8).

[Equation 9]

_{G = p} ^ ^ _{= p} (9) Select a fine line shape and Ε can be made sufficiently larger than Ε.

Energy gain. [0028] To return the domain wall 6 from "0" to "1", that is, to store magnetic energy in the element, between the second electrode 13 and the first electrode 11, the first electrode 11 and the central electrode 12 This can be done by measuring a voltage or current having a polarity opposite to that of the voltage or current pulse applied between them. As a result, the domain wall 6 can be moved again from the second domain wall holder 9 to the first domain wall holder 8. This operation corresponds to the initialization of the device when this device is used as a voltage amplification device.

 [0029] Next, the amplification factor of the mutual conversion element 1 of magnetic and electrical energy having the nanostructure of the present invention, which is calculated based on the specific magnetic wire substance and element shape, is shown.

Permalloy (FeNi alloy) is considered as a specific magnetic wire material. The thickness of the thin line and 50 nm, 10- ¹⁵ m ² (width 20 nm) the cross-sectional area at the position of "0" in FIG. 2, "1" 1.1 the cross-sectional area at the position of X 10- "m ² (width 220 nm), the cross-sectional area at the position of the center electrode 12 1. and ² X 10- ^{1 4} m 2 (width 240 nm). According to this ^{condition, a = 10 "n j /} m, K = 10 ⁵ j / m ³ and ex u

p = 0.7. With these parameters, expression (7), from equation (8), and ^{_{a w = 10 "m 3,}} E = 10-" J, E = 10- 18 J. Furthermore, the energy amplification in this case ab

 As the rate G, equation (10) is obtained.

 [Equation 10]

G = 7.7 (10)

[0030] A magnetic and electrical energy mutual conversion element having a nanostructure according to a second embodiment of the present invention will be described.

 FIG. 3 schematically shows a magnetic and electrical energy mutual conversion element 20 having a nanostructure according to the second embodiment of the present invention, where (A) is a cross-sectional view and (B) is a plan view. It is. As shown in FIG. 3, the magnetic and electrical energy conversion element 20 having a nanostructure is composed of a nanostructure and has a positional relationship obtained by rotating the thin wire 1 shown in FIG. 1 by 90 °. . In order of the lower force, the first layer 22 having a wider width, the second layer 23 continuous with the first layer 22 and having a wedge-like width, and the second layer 23 having a width that is continuous with the second layer 23 It is composed of a third layer 24 that gradually becomes thin and a fourth layer 25 that is continuous with the third layer 24 and has a wide layer width.

 The width of each part of the nanostructure 20 is d for the width of the first layer 22 and d for the narrowest width of the second layer 23.

 1 2

The widest width of the third layer 24 is d and the narrowest width is d, and the width of the fourth layer 25 is d And d>d>d> d and d> d. Nano structure

1 3 2 3m 4 3m

 The structure 20 has a thickness L in the stacking direction (Y-axis direction) and a length in the direction perpendicular to the paper surface (Z-axis direction).

 z

 [0031] Between the one end portion 22 of the nanostructure and the second layer, the width is d in order to hold the domain wall.

 2 A first domain wall holder 23A is formed. Between the other end 25 of the nanostructure 25 and the fourth layer 25, a second domain wall holder 24A having a width d is formed to hold the domain wall.

 3m

 Yes.

 [0032] In the nanostructure 20, the first electrode 26 connected to the first layer 22 as one end, the second electrode 27 connected to the fourth layer 25 as the other end, A central electrode 28 connected to the vicinity of the boundary between the second layer 23 and the third layer 24 is formed. Therefore, in the magnetic / electrical energy mutual conversion element 20 having a nano structure, the cross-sectional area of the portion where the electrodes 26, 27, 28 are connected is large, and the width disposed between these electrodes. The cross-sectional areas of the narrow first domain wall holder 23A and the second domain wall holder 24A are reduced. The cross-sectional area is set so that the magnetic energy of the first domain wall holder 23A is larger than the magnetic energy 24A of the second domain wall holder.

 FIG. 3 (B) is a plan view seen from the one end 25 side of the upper part of the nanostructure shown in FIG. 3 (A). The first electrode 26, the second electrode 27, and the central electrode 28 are connected to each other. The electrode wirings 26A, 27A, and 28A are respectively formed. These electrode wirings 26A, 27A, 28A can be formed through a plurality of interlayer insulating layers so as not to contact each other. In the illustrated case, the first and second domain wall holders 23A, 24A are formed by gradually changing the dimensions linearly from the end side and the center side. May be formed by a curve that is not a straight line as shown, or a combination of a straight line and a curve.

[0034] In this manner, in the magnetic and electrical energy-conversion element having the nanostructure according to the second embodiment of the present invention, the nanostructure 20 is made of a magnetic material having electron conductivity. The first and second electrodes 26 and 27 are connected to both ends of the nanostructure 20, and the center electrode 28 is connected to the center of the nanostructure. A first domain wall holder 23A that can hold a domain wall between the first electrode 26 and the center electrode 28 of the nanostructure 20 and a domain wall between the second electrode 27 and the center electrode 28 of the nanostructure 20 Second domain wall holder 24A And there will be a power waiting.

 Here, the magnetic energy of the first domain wall holder 23A and the second domain wall holder 23A, 24A is smaller than the magnetic energy of the both ends of the nanostructure 20, and the magnetic energy of the first domain wall holder 23A is the first It is configured to be larger than the magnetic energy 24 A of the domain wall holder 2. In the nanostructure 20 configured as described above, similarly to the magnetic and electrical energy conversion element 1 having a nanostructure having a thin line force, an input voltage or current is applied between the first electrode 26 and the central electrode 28. Thus, it is possible to take out electrical energy from the center electrode 28 and the second electrode 27 through the output voltage or current and take out the electrical energy.

 The magnetic / electrical energy mutual conversion element 20 having the nanostructure of the present invention can be formed by a thin film forming technique and a processing method such as etching, so that its thickness in the vertical direction (Y direction in FIG. 4) Easy to control. For this reason, the vertical length L of the nanostructure 20 can be made smaller than that in the case of the nanostructure 1 having a planar structure, and therefore, the magnetic and electrical energy mutual conversion element 20 having the nanostructure 20 It is advantageous to reduce the internal resistance and increase its integration density.

 [0036] A magnetic and electrical energy mutual conversion element having a nanostructure according to a third embodiment of the present invention will be described.

 FIG. 4 schematically shows the structure of the magnetic and electrical energy mutual conversion element 30 having the nanostructure according to the third embodiment of the present invention, where (A) is a cross-sectional view and (B) is a cross-sectional view. FIG.

 The nanostructure of the mutual conversion element 30 of magnetic and electrical energy shown in FIG. 4 (A) has a structure in which the lower force on the paper is also stacked on the first hard magnetic layer 34 in order. The first soft magnetic layer 35, the second hard magnetic layer 36, the second soft magnetic layer 37, and the third hard magnetic layer 38 are stacked.

In the nanostructure 30, the first electrode 40 is connected to the first hard magnetic layer 34 which is one end thereof, and the second electrode 41 is connected to the third hard magnetic layer 38 which is the other end thereof. A central electrode 42 is connected near the boundary between the second hard magnetic layer 36 and the second hard magnetic layer 36. The ferromagnetic structure 33 has a thickness L in the stacking direction (Y-axis direction) and a width W. The

 FIG. 4 (B) is a plan view of the nanostructure 30 of FIG. 4 (A) in which the side force of the third hard magnetic layer 38 on the upper side is also seen. The first electrode 40 and the second electrode 41 Electrode wirings 44, 45, and 46 are formed on the center electrode 42, respectively. These electrode self-intersecting wires 44, 45, 46 can be formed through a plurality of interlayer insulation layers, such as V, which are not in contact with each other.

 [0039] The first to third hard magnetic layers 34, 36, and 38 are made of a hard magnetic material that is a material in which the direction of the magnetic field hardly changes, and an iron-platinum alloy or the like can be used. This hard magnetic material is also called a hard magnetic material. The first and second soft magnetic layers 35 and 37 also have a hard magnetic material force, which is a material in which the direction of the magnetic moment is extremely easy to rotate, and permalloy or the like can be used. This soft magnetic material is also called a soft magnetic material.

 [0040] In the nanostructure 30, the first soft magnetic layer 35 inserted between the first and second hard magnetic layers 34 and 36 becomes a stable low energy layer holding a domain wall, and the first A domain wall holder is formed. The second soft magnetic layer 35 inserted between the second and third hard magnetic layers 36 and 38 becomes a stable low-energy layer that holds the domain wall, and serves as the second domain wall holding portion. Here, the magnetic energy of the first domain wall holding unit and the second domain wall holding unit is smaller than the magnetic energy of the both ends of the nanostructure 30. The magnetic energy of the first domain wall holding unit is the second domain wall. It is configured to be larger than the magnetic energy of the holding part. The gradient of energy generated between the hard magnetic layer and the soft magnetic layer is determined by the mixing ratio of each magnetic substance at the boundary between each hard magnetic layer 34, 3 6, 38 and each soft magnetic layer 35, 37. It can be formed by gradually changing.

 [0041] In the nanostructure 30, the magnetic energy per unit area of the hard magnetic layer σ

 (hard) is larger than the magnetic energy σ (soft) per unit area of the soft magnetic layer, the difference in potential energy between the first and second domain wall holders can be obtained. In other words, the potential energy of the domain wall holder is given by the product of the magnetic energy σ per unit area multiplied by the section area 面積, that is, σ X Α. In the magnetic structure 33, the cross-sectional area A is constant. However, the magnetic energy of the hard magnetic layer and that of the soft magnetic layer are different, so that a potential energy difference between the domain wall holders can be generated.

[0042] Magnetic energy per unit area when the soft magnetic layer is permalloy σ (soft) Is 10 ³ j / m ² as mentioned above. As the hard magnetic layer iron - magnetic energy per unit area in the case of platinum alloy sigma (hard) becomes 8 X 10- ³ j / m ² approximately. Here, as a material parameter, the magnitude of the exchange interaction is A = 10— ^u jZm,

 ex Uniaxial magnetic anisotropy constant

K = 7 × 10 ⁶ j / m ³ . If the nanostructure 30 has a regular tetragonal pattern, the area is 1 X ^10-15 m ² when its width W (dimension in the X-axis direction in Fig. 4) is 32 nm. this

1

Permalloy and iron in the area -. Magnetic energy of platinum alloy, respectively, a ^{1 X 10 "18 J, 8} X 10- 18 J Thus, the magnetic energy barrier between the soft magnetic layer and the hard magnetic layer in this case Δ E is calculated to be ^{7 X 10- 18 J (43. 7eV} ). this energy barrier delta E is sufficiently large! /, so interconversion element 30 of the magnetic and electric energy having a nano structure of the present invention Can operate stably at normal use temperature.

[0043] In the nanostructure 30, a difference in positional energy can be provided by changing the thickness of the soft magnetic layer in the stacking direction. The reason is described below.

 The width of the domain wall (in the Y-axis direction in Fig. 4 (A)) determines the magnitude of the exchange interaction A.

ex Uniaxial magnetic anisotropy constant (A / K) ^1/2 , which is the square root of the value divided by K. The width of this domain wall is 10η u ex u

 m. That is, when the soft magnetic layer is thickened, the domain wall, that is, the portion where the magnetic moment is spatially changed almost overlaps the soft magnetic layer, so that the magnetic energy is the above-mentioned σ (soft) Thus, the lowest energy state among the nanostructures 30 is realized.

 On the other hand, if the soft magnetic layer is made thinner and smaller than the domain wall width, the domain wall actually overlaps with the adjacent hard magnetic layer, so the energy of the domain wall is σ (soft) and σ (hard) Is given by an intermediate value. In this case, the energy of the domain wall is higher than that in the case of the thick soft magnetic layer. Of course, since the energy in this case is lower than the σ (hard) in the case where the soft magnetic layer is not provided, it sufficiently functions as a domain wall holding portion. Therefore, the soft magnetic layer serving as the second magnetic holding portion on the low energy side needs to be thicker than the domain wall width, and the soft magnetic layer serving as the first magnetic wall holding portion on the high energy side needs to be thinner than the domain wall width. .

[0044] In the mutual conversion element 30 for magnetic and electrical energy having the nanostructure of the present invention, the first and second soft magnetic layers 35 and 37 are used as the first and second magnetic holding portions, respectively. Thus, the magnetic and electrical energy mutual conversion element 1 having the nanostructure shown in FIG. 1 can be operated. In the formation of the nanostructure 30, it is not necessary to form a narrow area of W at a predetermined position in the stacking direction unlike the nanostructure 20, so

 2

 Manufacture is easy because the width W should be uniform in the straight direction. Because of this, nanostructure

 1

 Since the vertical length L of the body 30 can also be made smaller than that of the nanostructure 1 having a planar structure, the internal resistance of the magnetic and electrical energy conversion element 30 having the nanostructure can be reduced and integrated. It is advantageous to increase the density.

 [0045] The width and film thickness of the magnetic and electrical energy mutual conversion elements 20, 30 having the nanostructure of the present invention are indispensable to be nanometer size. That is, when the magnetic wire width and film thickness are 1 μm or more, the domain wall is not uniformly driven by the current, and the structure of the domain wall itself changes (see Non-Patent Document 3).

 [0046] Next, an integrated circuit of magnetic and electrical energy mutual conversion elements having the nanostructure of the present invention will be described. FIG. 5 is a perspective view schematically showing a configuration of an integrated circuit using a magnetic and electrical energy mutual conversion element having the nanostructure of the present invention.

 As shown in FIG. 5, in the integrated circuit 50 using the magnetic and electrical energy mutual conversion elements having nanostructures, the X-direction electrode wiring 52 and the Y-direction electrode wiring 54 cross each position. In this configuration, the nanostructures 20 are arranged in a matrix. Y-direction electrode wiring 52 and X-direction electrode wiring 54 are connected to the first and second electrode layers 26 and 27 of each nanostructure 20 arranged in the matrix form, respectively. An electrode wiring 56 is connected to the electrode 28. The nanostructure is not limited to the magnetic and electrical energy conversion element 20 having the nanostructure according to the second embodiment, and the nanostructures 1 and 30 according to the first embodiment and the third embodiment are used. May be.

 [0047] The magnetic and electrical energy mutual conversion elements having the nanostructure of the present invention can be integrated to increase the stored magnetic energy. If such an integrated circuit 50 is incorporated in an integrated circuit that is a semiconductor device, it can be used as an auxiliary power source in the event of a power failure.

[0048] The magnetic and electrical energy mutual conversion element having the nanostructure of the present invention includes the following: It can be manufactured as follows.

 First, a magnetic thin film to be a nanostructure is deposited on a substrate with a predetermined thickness. As the magnetic material, permalloy, iron, iron-cobalt alloy, iron-platinum alloy, samarium-cobalt alloy and the like can be used. As a deposition method, a sputtering method which is a physical vapor deposition method can be used. As this substrate, an MgO substrate or a substrate obtained by depositing MgO on a Si substrate coated with an insulating layer can be used.

 Next, the magnetic wire 1 and the nanostructures 20, 30 are formed by the mask process and etching process, thereby producing magnetic and electrical energy mutual conversion elements 1, 20, 30 having the nanostructures. can do.

[0049] When the peripheral circuit for controlling the voltage and current between the electrodes of the magnetic and electrical energy mutual conversion element having the nanostructure of the present invention is formed by an integrated circuit, the nanostructure manufactured by the above process is used. The entire substrate including the bodies 1, 20, and 30 is further covered with an insulating film, and after opening only the electrodes of the nanostructures 1, 20, and 30, the mutual magnetic and electrical energy of each nanostructure is obtained. The wiring of the conversion element memory may be performed. In addition, when the peripheral circuit of the magnetic and electrical energy conversion elements 1, 20, and 30 having the nanostructure of the present invention is formed by a Si MOS transistor, the Si peripheral circuit is formed first, and then Thus, the magnetic and electrical energy mutual conversion elements 1, 20, and 30 having the nanostructure of the present invention may be formed. In addition to sputtering, each material can be deposited using conventional thin film deposition methods such as CVD, vapor deposition, laser ablation, and MBE. In addition, light exposure, EB exposure, or the like can be used for a mask process for forming electrodes of a predetermined shape or wiring of an integrated circuit.

[0050] The present invention is not limited to these examples, and various modifications are possible within the scope of the invention described in the claims, and they are also included in the scope of the present invention. Not too long.

 Industrial applicability

[0051] As understood from the above description, according to the mutual conversion element of magnetic and electric energy having the nanostructure of the present invention, the electric energy is converted into magnetic energy and stored, and the stored magnetic field is stored. Energy can be converted into electrical energy and extracted. For example, the voltage can be amplified using the stored magnetic energy as an energy source. Conventional storage of magnetic energy requires a large and bulky coil to extract the magnetic force and electrical energy that is generated by magnetizing a ferromagnetic material in a specific direction. On the other hand, according to the element of the present invention, it is only necessary to apply a voltage or current to the extraction electrode provided in the thin wire or the laminated structure. Therefore, the device can be miniaturized and integrated, and has high energy efficiency. It is extremely useful if it is used in a device that needs to convert electrical energy into magnetic energy and store it, and then convert the stored magnetic energy into electrical energy.

Claims

The scope of the claims  [1] having a nanostructure made of a magnetic material having electronic conductivity,  First and second electrodes connected to both ends of the nanostructure;  A central electrode connected to the central portion of the nanostructure;  A first domain wall holder capable of holding a domain wall between the first electrode of the nanostructure and the central electrode;  A second domain wall holding unit capable of holding a domain wall between the second electrode of the nanostructure and the central electrode;  The magnetic energy of the first domain wall holding unit and the second domain wall holding unit is smaller than the magnetic energy at both ends of the nanostructure. The magnetic energy of the first domain wall holding unit is the second energy level. It is configured to be larger than the magnetic energy of the domain wall holder,  The electrical energy is applied between the first electrode and the central electrode via an input voltage or current, and the amplified output electrical energy is extracted from between the central electrode and the second electrode via the output voltage or current. An interconversion element of magnetic and electrical energy having a nanostructure.  [2] The magnetic energy is stored by applying a voltage or current having a polarity opposite to the input voltage or current between the first electrode and the central electrode between the first electrode and the second electrode, An interconversion element of magnetic and electrical energy having the nanostructure according to claim 1.  [3] The nanostructure includes a first region having a wide thin line, a second region in which the width of the thin line contiguous to the first region is constricted in a wedge shape, and a continuous region in the second region. The width of the thin line to be gradually reduced is composed of a third area, and the width of the thin line continuous to the third area is wide, and the fourth area,  The width of the first area is d, the narrowest width of the second area is d, and the third area  1 2  The widest width of the region is d, the narrowest width is d, and the width of the fourth region is d  3 3m 4 When d> d> d> d and d> d 1 3 2 3m 4 3m The first electrode is provided in the first region, and the first electrode is provided on the second region side of the third region. The magnetic and electrical energy conversion element having the nanostructure according to claim 1, wherein a central electrode is provided and a second electrode is provided in the fourth region. [4] The nanostructure has a laminated structural force, and both the end portions and the center portion thereof are wide, and the first and second domain walls having a narrow width capable of holding a domain wall between each end portion and the center portion. 2. The magnetic / electrical energy mutual conversion element having a nanostructure according to claim 1, wherein the holding portion is formed!  [5] The nanostructure according to claim 1, wherein the material of the nanostructure is any one of permalloy, iron, an iron-cobalt alloy, an iron-platinum alloy, and a summary-cobalt alloy. Magnetic and electrical energy mutual conversion element. [6] The nanostructure includes a first hard magnetic layer, a first soft magnetic layer, a second hard magnetic layer, and a first hard magnetic layer. It has a structure in which 2 soft magnetic layers and 3rd hard magnetic layers are laminated,  The first electrode is connected to a first hard magnetic layer that is one end of the nanostructure, and the second electrode is connected to a third hard magnetic layer that is the other end of the nanostructure. The central electrode is connected to the second hard magnetic layer,  2. The magnetic and electric energy having a nanostructure according to claim 1, wherein the first soft magnetic layer and the second soft magnetic layer serve as the domain wall holding unit for holding a domain wall. Mutual conversion element. 7. The magnetic and electrical energy mutual conversion element having a nanostructure according to claim 6, wherein the hard magnetic layer has an iron-platinum alloy force and the soft magnetic layer has a permalloy force.  [8] The magnetic and electrical energy having the nanostructure according to any one of claims 1 to 7, wherein the magnetic and electrical energy conversion element force matrix having the nanostructure is arranged in a matrix shape. Electric energy mutual conversion element.