JP2008071720A - Battery, battery system, and microwave transmitter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To elucidate a mechanism for converting spin polarization current to current in a non-magnetic layer, to provide a battery apparatus which uses this mechanism and has a layered structure of ferromagnetic layer/non-magnetic layer/ferromagnetic layer, and to provide a method of controlling magnetization and a microwave transmitter which use phenomenon that current applied to a non-magnetic layer is converted to spin polarization current. <P>SOLUTION: A battery cell includes at least a first ferromagnetic metal layer 13, a non-magnetic metal layer 12, and a second ferromagnetic metal layer 11 in this order. Further, the battery cell includes a counter electrode for taking out current from a facing end face 23 of the non-magnetic metal layer 12. In this battery cell, the first ferromagnetic metal layer and the second ferromagnetic metal layer each has a thickness of 1 nm to 200 nm, and magnetization directions 14 of the first ferromagnetic metal layer and the second ferromagnetic metal layer are changed together when magnetic field 21 is applied. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a battery, a battery system, and a microwave transmission device.

  In recent years, research on so-called spin electronics has been actively conducted in order to actively utilize the degree of freedom of spin in electronics. Among these, magnetoresistive random access memory (MRAM) using spin injection magnetization reversal is known as the most ambitious proposal.

  Spin injection magnetization reversal means, for example, a three-layer structure of a ferromagnetic layer (F1 layer) / non-magnetic layer (N layer) / ferromagnetic layer (F2 layer), where the thickness of the F1 layer is F2. When the bias current is applied in a direction perpendicular to the laminated surface when the thickness is sufficiently smaller than the thickness, a stronger torque acts on the magnetic moment of the F2 layer than the magnetic moment of the F1 layer, and only the magnetic moment of the F2 layer rotates. Refers to the phenomenon of reversal (for example, see Non-Patent Document 1).

  The torque acting on the magnetic moment in each layer is related to the change in spin-polarized current. The spin-polarized current is a spin flow of conduction electrons having a spin angular momentum in a specific direction.

Attempts have been made to reverse the magnetization direction by a spin-polarized current without applying a bias voltage in a direction perpendicular to the laminated surface (see, for example, Non-Patent Documents 2 and 3). When a spin in a specific direction is forcibly injected into the F1 layer by applying a pulsed magnetic field or the like, the angular momentum of the spin is transferred at the interface between the F1 layer and the N layer and the interface between the N layer and the F2 layer. An increase in the spin-polarized current acts as a torque on the magnetic moment of the F2 layer. When the torque due to this spin-polarized current is larger than the braking torque, it is expected that the magnetization direction of the F2 layer can be reversed.
Rooftop, Suzuki, Journal of Japan Society of Applied Magnetics, Vol. 28, no. 9 (2004) 937-948, Ando, Minakami, Miyazaki Solid Physics 40 1 (2005) 35-42 RIKEN News No. 281, Research Frontier “Manipulating Spin Flow”, November 2004

  The present invention clarifies the mechanism by which spin-polarized current is converted into current in the nonmagnetic layer, and uses this mechanism to provide a battery device having a laminated structure of ferromagnetic layer / nonmagnetic layer / ferromagnetic layer, and It is an object of the present invention to provide a magnetization control method and a microwave transmission device using a phenomenon that a current applied to a nonmagnetic layer is converted into a spin-polarized current.

A battery cell according to the present invention includes at least a first ferromagnetic metal layer, a nonmagnetic metal layer, and a second ferromagnetic metal layer in this order, and for taking out current from opposing end faces of the nonmagnetic metal layer. A battery cell having a counter electrode, wherein each of the first ferromagnetic metal layer and the second ferromagnetic metal layer has a thickness of 1 nm to 200 nm, and the first ferromagnetic metal layer and the second ferromagnetic metal layer The magnetization direction of the metal layer changes together when a magnetic field is applied.
The battery according to the present invention is obtained by stacking the battery cells via an insulating layer.
A battery system according to the present invention includes the battery cell or the battery, and a magnetic field generator capable of applying a magnetic field in a direction perpendicular to a stack surface of the battery cell or the nonmagnetic metal layer of the battery. .
The microwave transmission device according to the present invention includes at least a first ferromagnetic layer, a nonmagnetic layer, and a second ferromagnetic layer in this order, and allows a current to flow in a direction parallel to the laminated surface of the nonmagnetic layer. A magnetic film cell having an in-plane size smaller than the domain wall width, an AC power source capable of applying an AC current to the magnetic film cell via the counter electrode, and a frequency and magnetization of the AC power source It is a microwave transmission device provided with a synchronizing means with a vibration period.
The method according to the present invention includes at least a first ferromagnetic layer, a nonmagnetic layer, and a second ferromagnetic layer in this order, a magnetic film cell having an in-plane size smaller than the domain wall width, and a stack of the magnetic film cells. In a spin-injection magnetization switching element comprising a first counter electrode provided in a first ferromagnetic layer and a second ferromagnetic layer in order to pass a current in a direction perpendicular to the plane, the first ferromagnetic layer and A method for switching the magnetization directions of the second ferromagnetic layer to each other in parallel or anti-parallel, wherein the second ferromagnetic layer is provided to allow a current to flow in a direction parallel to the laminated surface of the first counter electrode and the nonmagnetic layer. Connecting a polarity variable power source to each of the counter electrodes, and passing a direct current to the magnetic film cell through the first counter electrode and the second counter electrode using the power source. Is the method.

  According to the present invention, it is possible to obtain a battery that can be charged in a non-contact manner for a very short time and is less likely to cause a decrease in capacity.

Hereinafter, the present invention will be described in detail with reference to the drawings. The same members are denoted by the same reference numerals. In addition, this invention is not restrict | limited to the form demonstrated below.
The battery cell of the present invention includes a first ferromagnetic metal layer, a nonmagnetic metal layer, and a second ferromagnetic metal layer in this order.
In the present specification, when the first ferromagnetic metal layer and the second ferromagnetic metal layer are not distinguished, they are simply referred to as a ferromagnetic metal layer.
Although it does not specifically limit as a material of a ferromagnetic metal layer, For example, cobalt, an iron-nickel alloy (Py), etc. are employable. The first ferromagnetic metal layer and the second ferromagnetic metal layer may be made of the same material or different materials. Each ferromagnetic metal layer may include two or more layers made of different materials. As the material of the nonmagnetic metal layer, for example, copper (Cu), platinum (Pt), gold (Au), etc. can be adopted. In particular, when used as a battery cell, the spin-orbit interaction described later is compared. Therefore, platinum (Pt) and gold (Au) are preferably used.
The impurity concentration of the nonmagnetic metal is preferably included to the extent that conduction electron scattering due to the spin-orbit interaction described later occurs moderately, for example, 1 × 10 ¹⁹ cm ⁻³ to 1 × 10 ²⁰ cm ^−. Can be ³ .
The ferromagnetic metal layer and the non-magnetic metal layer used in the present invention can use a conventionally known semiconductor processing process technique, and can be formed by a vacuum deposition method, a magnetron sputtering method, or the like.

  The ferromagnetic metal layer needs to be formed thin in order to be used as a battery cell. The thickness of the ferromagnetic metal layer depends on the type of the ferromagnetic metal and the type of the adjacent nonmagnetic metal layer.For example, when using cobalt as the ferromagnetic metal and platinum as the nonmagnetic metal layer, It can be 1 nm to 200 nm. A preferred lower limit is 2 nm and a preferred upper limit is 40 nm. When the layer thickness is within the above range, the spin-polarized current can flow efficiently. The layer thickness of the first ferromagnetic metal layer and the layer thickness of the second ferromagnetic metal layer may be the same or different.

If the layer thickness of the nonmagnetic metal layer is too thick, the spin direction may be disturbed by spin diffusion and the spin-polarized current may not flow. For example, when using platinum, 1 nm to 10 nm, when using gold, 1 nm to 50 nm is preferable.
Each upper limit is the spin diffusion length at the respective room temperature.

In the battery cell of the present invention, the magnetization directions of the two ferromagnetic metal layers change together when a magnetic field is applied. In this specification, “the magnetization direction of the ferromagnetic metal layer changes” means that a magnetic field applied in a direction perpendicular to the laminated surface or a direction perpendicular to the laminated surface is added to the spin of electrons in the ferromagnetic metal layer. This means that the torque applied from outside the system by the applied current exceeds the braking torque, and the spin-polarized current flows out to the nonmagnetic metal layer.
In the battery cell of the present invention, the magnetization direction of any ferromagnetic metal layer does not need to be fixed in one direction. That is, it should be distinguished from the spin-injection magnetization reversal element described later in that it does not have a magnetization fixed layer (pinned layer) whose magnetization direction does not change and that it is not necessary to apply a current perpendicular to the laminated surface. It is.

  In the battery cell of the present invention, it is preferable that the magnetization directions of the first ferromagnetic metal layer and the second ferromagnetic metal layer have an antiparallel relationship when no magnetic field is applied. When anti-parallel, when an external magnetic field is applied perpendicular to the laminated surface, magnetization tends to go in the direction of the external magnetic field, so it tends to be in a non-collinear state and a state in which a spin-polarized current flows between both layers . In this specification, “non-collinear” means a state that is not parallel or anti-parallel.

As a method of laminating the first ferromagnetic metal layer and the second ferromagnetic metal layer so that the magnetization directions are antiparallel, interlayer exchange interaction (also referred to as Rudermann-Kittel-Kasuya-Yoshida (RKKY) interaction) Is used. The feature of this interaction is that when the thickness of the nonmagnetic layer changes, the magnitude of the interaction of magnetization between the ferromagnetic layers is attenuated by the cube of the distance while oscillating. The oscillation period is about the Fermi wavelength (10 ⁻¹⁰ m) of the conduction electrons. Therefore, if the thickness is changed appropriately, the sign of the interaction can be changed, so that the magnetizations can be antiparallel to each other.

Regarding the battery cell of the present invention, the operating principle is not limited to a specific theory, but the presently considered principle will be described below.
First, as shown in FIG. 2, the magnetization direction 14 in the antiparallel state in the first ferromagnetic metal layer 11 and the second ferromagnetic metal layer 13 is applied, for example, by applying an external magnetic field [H _ex ] 21. In a non-collinear state (state A).
In such a non-collinear state, a spin-polarized current js proportional to the magnitude of the outer product m1 × m2 of the magnetization directions m1 and m2 of each layer flows in the direction perpendicular to the laminated surface, that is, the z direction. The amount of spin-polarized current is maximized when the directions of m1 and m2 are orthogonal. If the in-plane size (area) of each layer is increased, the amount increases in proportion to the area. The spin-polarized current js here is expressed as js = j ↑ −j ↓ where the flow of conduction electrons whose spin direction is upward is the vector amount j ↑ and the flow of downward conduction electrons is the vector amount j ↓. Defined.
As shown in FIG. 3, under the condition where the battery is not connected to the load, the upward spin conduction electrons 31 and the downward spin conduction electrons 32 flow in opposite directions 33, and the spin current without a net current is generated. This is a situation where only the flow is occurring. Therefore, this spin-polarized current is an equilibrium flow without energy dissipation due to Joule heat.
In the situation of FIG. 2, the spin direction is based on the vector outer product direction of m1 and m2, that is, the y-axis.

The nonmagnetic metal layer 12 can be made of Pt, Au or the like as described above. The nonmagnetic metal layer 12 contains impurities, and conduction electrons undergo spin-orbit interaction due to such impurities. In the scattering of conduction electrons due to this interaction, the probability that the scattering occurs in the upward spin and the downward spin is the same, but the scattered directions are opposite to each other. In the case of the above-described equilibrium spin-polarized current, the conduction electrons flow 41 of the upper and lower spins are opposite to each other along the z-axis, so the directions scattered by the spin-orbit interaction are the same, and the spin polarization A net flow in a direction perpendicular to the current flow results in a Hall current 42 (FIG. 4).
The Hall current vector j is considered to be proportional to the outer product js × y of the spin-polarized current vector js and the spin direction (y-axis direction unit vector is represented by y). That is, the direction of the hole current flow is a direction perpendicular to the plane formed by the y-axis and the z-axis, that is, the x-direction.
When the hole current 42 reaches the boundary surface of the nonmagnetic metal layer, relaxation occurs. Eventually, charge 52 is accumulated on the boundary surface (opposing end surface) 51 of the nonmagnetic metal layer, and a potential difference is generated between the boundary surfaces. (Fig. 5)
The above is the mechanism for converting the spin-polarized current into the in-plane current. This is the reverse action of generating a spin current in an electric field and is called the reverse spin Hall effect.

Hereinafter, it will be estimated how much energy can be extracted from the battery using the battery cell of the present invention. The material of the two ferromagnetic metal layers is cobalt (Co). Since the Curie temperature of cobalt is about Tc = 1400K, the exchange interaction energy is
k _B Tc = 1400 × 1.4 × 10 ⁻²³ = 2 × 10 ⁻²⁰ J
(K _B : Boltzmann constant) When the lattice spacing is 3.5 × 10 ⁻¹⁰ m, the energy per unit volume stored when the two ferromagnetic layers are brought into a non-collinear state is estimated to be 4.6 × 10 ⁸ J / m ^3. . When this is converted into a unit of Wh / L (watt hour / liter), 1 Wh = 3600 J, L = 1 × 10 ⁻³ m ³ , 4.6 × 10 ⁸ /3.6×10 ⁶ = 128 Wh / L It becomes.
And the relationship with the current J induced by the spin-polarized current Js flowing between the non-collinear ferromagnetic metal layers is
J = σ _ISHE Js
The proportional coefficient is the conversion efficiency from the spin-polarized current to the current. In general, σ _ISHE can be written as σ ₀ / σ _SH (where σ ₀ is the longitudinal electrical conductivity (for example, current flows in the x direction with respect to the electric field in the x direction), and σ _SH is the spin hole current conductivity ( For example, for an electric field in the y direction, a spin current having a z direction spin flows in the x direction). Therefore, the ratio of spin-polarized current to current (conversion efficiency) Js / J = σ _ISHE ⁻¹ = σ _SH / σ ₀ , which corresponds to the magnitude η _S0 of the spin-orbit interaction in the nonmagnetic metal layer. Proportionally proportional. According to literature (Concept in Spin Electronics, S. Takahashi et al., P365, right end η _{s0 in} Table 8.1), it is about 0.03 to 0.04 for copper (Cu). There is no data for gold or platinum, but if this value is used as a conversion efficiency, the energy density that can be taken out as a battery is the stored energy density x conversion efficiency. If the energy density of a recent battery is several hundred Wh / L and the conversion efficiency is 10% (0.1), the energy density of the battery cell of the present invention is one digit smaller, but the conversion efficiency can be increased by one digit. The same.

When the above battery density and conversion efficiency values are used, and the size of each of the ferromagnetic metal layer and the nonmagnetic metal layer of the battery cell is, for example, 1 cm long × 1 cm wide × 10 nm thick, the stored energy is 2.3 × 10 ⁻⁴ J. Here, assuming that the extracted current is about 1 [V] 1 [mA] = 1 × 10 ⁻³ J / s, the discharge is performed in about 2.3 × 10 ⁻⁴ / 1 × 10 ⁻³ = 0.23 seconds. It will be.

The battery cell of the present invention is provided with a counter electrode for taking out current from opposite end surfaces of the nonmagnetic metal layer.
The opposing end surfaces are boundary surfaces where the in-plane current in the nonmagnetic metal layer is relaxed. The boundary surface preferably coincides with a surface perpendicular to the collinear magnetization direction.
Since the nonmagnetic metal layer needs to be formed very thin, the area of the end face is very small. Therefore, the counter electrode electrically connected to the nonmagnetic metal layer can be, for example, a take-out electrode so that current can be easily taken out by the lead wire. The extraction electrode can be provided by forming a nonmagnetic metal layer so as to protrude from the laminated surface of the first ferromagnetic metal layer as well as on the surface of the first ferromagnetic metal layer. Next, the second ferromagnetic metal layer can be laminated after masking the extraction electrode portion of the nonmagnetic metal layer.
As the material of the counter electrode, palladium, solder, or the like can be employed so that the contact resistance between the lead wire and the nonmagnetic metal layer is reduced.

The area (in-plane size) of the battery cell of the present invention can be several cm ² if the magnetization structure in the ferromagnetic layer can have a single domain structure.

Since the battery cell of the present invention has a very simple structure, it can be used as a small secondary battery incorporated in another device. However, in order to ensure the capacity of an existing general-purpose battery, it is preferable to stack the battery cells in a direction perpendicular to the stacking surface. A battery in which the battery cells are stacked with an insulating layer interposed therebetween is also an aspect of the present invention.
Examples of the material for the insulating layer include alumina (Al ₂ O ₃ ), which is an amorphous material that is also used for TMR (tunnel magnetoresistance) elements, and magnesium oxide (MgO), which is a crystalline material. Examples of the method for laminating the insulating layer include a magnetron sputtering method. The thickness per layer of the insulating layer can be 1 nm to 10 nm.
The number of stacked battery cells is not particularly limited. For example, by stacking tens of thousands of layers, the battery cells can be maintained for several hours with a current of about 1 mA.

  When the counter electrode of the nonmagnetic metal layer is connected with a lead wire, as shown in FIG. 6, a current flows between the lines due to the potential difference, and work can be performed on the load 61 outside the system. On the other hand, as a price, the magnetization direction 14 returns to antiparallel, and no equilibrium spin-polarized current flows between the layers. And by using a magnetic field etc. again, the magnetization direction of each layer can be made into a non-collinear state (this respond | corresponds to charge), and it can return to the said state A.

A battery system including the battery and a magnetic field generator capable of applying an effective magnetic field in a direction perpendicular to the laminated surface of the nonmagnetic metal layers of the battery is also an aspect of the present invention.
The magnetic field generator does not need to be able to apply a magnetic field strictly perpendicular to the laminated surface, and may be any device that can apply a magnetic field component perpendicular to the laminated surface. The magnetic field component perpendicular to the laminated surface is called an effective magnetic field.
As a method for applying such an effective magnetic field, a ferromagnetic resonance method (FMR), a method for applying a pulsed magnetic field, or the like can be employed.
The discharge operation to the outside in the battery cell or battery of the present invention and the charge operation using the magnetic field generator are closed as operations, can be used many times, and are consumed or deteriorated as in a conventional battery. There is no portion, no capacity drop due to electrode deterioration, etc., and in principle it can be used semipermanently.

As described above, the battery system of the present invention performs charging by applying an external magnetic field. However, charging is performed by passing a current through the counter electrode provided on the battery cell of the present invention or the nonmagnetic metal layer of the battery. It is also possible to do.
The above-described spin-polarized current-current conversion mechanism generates a current via a spin-orbit interaction in the laminated surface of the nonmagnetic metal layer when the spin-polarized current flows. This relationship is a linear response relationship. That is, the spin polarized current is proportional to the current. Conversely, the current is proportional to the spin-polarized current.
Therefore, as shown in FIG. 7, by passing a current 72 in the surface of the nonmagnetic metal layer 12, a spin-polarized current 22 can be generated in a direction perpendicular to the laminated surface, and the spin-polarized current 22 is magnetized. Since it functions to provide the torque 73, the magnetization 14 in the ferromagnetic metal layers 11 and 13 can be brought into a non-collinear state.

[Application to spin-injection magnetization reversal element and microwave transmitter]
A spin-injection magnetization reversal element is an element having a multilayer film structure in which a ferromagnetic layer is bonded via a nonmagnetic layer basically in the same manner as the battery cell of the present invention, and is expected to be applied to an MRAM or the like. It is an element. In this element, a current flows in a direction perpendicular to the laminated surface, thereby maintaining a magnetization direction in a laminated surface of a ferromagnetic layer called a magnetization fixed layer 93 in a constant direction, and a ferromagnetic layer called a magnetization switching layer 91. It is possible to switch the magnetization direction in the laminated surface of the two layers and switch the magnetization direction of the two ferromagnetic layers to a parallel or anti-parallel state, utilizing the resistance difference between the parallel and anti-parallel states. An element for writing and reading magnetic information. In order to configure this spin-injection magnetization reversal element, the in-plane size of the magnetic film cell is preferably smaller than the domain wall width of the ferromagnetic material to be used, and is required to be on the order of 100 nmφ. More specifically, the in-plane size of the magnetic film cell is preferably at least 200 nmφ and 4 nmφ to 100 nmφ.
In the present specification, the “in-plane size” is the major axis length of the laminated surface of the ferromagnetic layers.
In such a spin-injection magnetization switching element, what is most desired to be improved is to lower the threshold current value required for the magnetization direction switch. If the effect of the above-described spin-polarized current-current conversion mechanism is incorporated in a conventional spin-injection magnetization reversal element as shown in FIG. 8, a spin that can assist the magnetization direction switch by the in-plane current of the nonmagnetic layer. It becomes possible to develop an injection magnetization switching element. That is, when a current is passed through the first counter electrode in a direction perpendicular to the laminated surface to switch the magnetization direction of the inversion layer, a direction parallel to the laminated surface of the nonmagnetic metal layer 92 as shown in FIG. In addition, a current is passed through the second counter electrode to induce a spin-polarized current in a direction perpendicular to the laminated surface. Due to the induced spin-polarized current, the torque 94 acts on the magnetization 14 of the magnetization switching layer 91, and the magnetization reversal can be promoted. To return to the original state, the direction of each current may be changed at the same time. The great merit of this method is that a decrease in the threshold current value required to flow in the direction perpendicular to the plane of the multilayer film in order to reverse the magnetization can be expected.

Since current flows also in the laminated surface, even if the current value flowing perpendicularly to the laminated surface decreases, the amount of torque required for inversion does not change. Is that it decreases. This is because reducing Joule heat loss due to electric current is one of the important issues for device development.
An inversion current in a conventional spin injection inversion element is I. The Joule heat at this time is represented by R as the resistance of the element.
Wa = RI ²
It becomes. On the other hand, in the present invention, the inversion current is I ₁ , and the current flowing in the laminated surface is I ₂ . Here, it is assumed that the condition of I = I ₁ + I ₂ is satisfied. The Joule heat in this case is

And Joule heat decreases.

Further, a surface provided with at least a first ferromagnetic layer, a nonmagnetic layer, and a second ferromagnetic layer in this order, and provided with a counter electrode for flowing a current in a direction parallel to the laminated surface of the nonmagnetic layer. A magnetic film cell having an inner size smaller than the domain wall width; an AC power supply capable of applying an alternating current to the magnetic film cell via the counter electrode; and a means for synchronizing the frequency of the AC power supply and the magnetization oscillation period The provided microwave transmission device is also one aspect of the present invention.
As shown in FIG. 10, by making the current flowing in the surface of the nonmagnetic layer 102 into an alternating current, the spin-polarized current 22 induced perpendicular to the laminated surface can be converted into an alternating current. As a result, the magnetization direction 14 in the ferromagnetic layer can be vibrated perpendicularly to the laminated surface, and resonance is caused by synchronizing the AC power supply frequency with this magnetization oscillation period by the synchronization means, thereby making the magnetization coherent. It is thought that vibration can be induced. That is, the microwave 104 can be transmitted. By making such a transmitting device on a substrate and making a receiving device on the same substrate or an adjacent substrate, non-contact data transmission between two parts having different properties becomes possible.

  In the present specification, the magnetic film cell used in the microwave transmission device does not need to have the magnetization direction of any ferromagnetic layer fixed in one direction, but is fixed in one direction. It may be a thing. The thickness of the first ferromagnetic layer and the second ferromagnetic layer in the magnetic film cell of the microwave transmission device may be in the same range as the thickness of the ferromagnetic metal layer in the battery cell of the present invention described above. However, it may be in the range of the layer thickness conventionally required for the spin transfer magnetization switching element. The in-plane size of the magnetic film cell in the microwave transmission device is required to be on the same order as that of the spin injection magnetization reversal element. More specifically, the cell size is preferably at least 200 nmφ and 4 nmφ to 100 nmφ.

The magnitude of the current of the AC power supply is preferably 1 × 10 ⁶ Acm ⁻² to 1 × 10 ⁷ Acm ⁻² . The AC frequency of the AC power supply is usually about 1 GHz, although the magnetization oscillation period has a value specific to the material of the ferromagnetic metal, and varies depending on the type of the ferromagnetic metal.

It is a schematic diagram which shows the state in which the magnetization direction of the 1st ferromagnetic metal layer and the 2nd ferromagnetic metal layer in the battery cell of this invention is antiparallel. It is a schematic diagram which shows the change of the magnetization direction when an external magnetic field is applied to the specific direction of the battery cell of this invention, and the direction of the spin polarization current which arises by it. It is a schematic diagram which shows the equilibrium state of a spin polarization current. It is a schematic diagram which shows the state in which the hole current was produced by the spin-polarized current in the nonmagnetic metal layer of the battery cell of this invention. It is a schematic diagram which shows the state which the electric potential difference produced in the interface of a nonmagnetic metal layer by Hall current. It is a schematic diagram which shows the state from which the magnetization direction of F1 layer and F2 layer becomes antiparallel in connection with the extraction of the electric current by connecting between interface surfaces. By passing a current through the laminated surface of the nonmagnetic metal layer, a spin-polarized current is generated in a direction perpendicular to the laminated surface, and the magnetization directions of the first ferromagnetic metal layer and the second ferromagnetic metal layer are changed again. It is a schematic diagram which shows the one aspect | mode of the charge method to a battery which becomes non-collinear. It is a schematic diagram which shows the principle of operation of the conventional spin injection magnetization reversal element. It is a schematic diagram which shows the operation | movement principle of the spin injection magnetization reversal element of this invention. It is a conceptual diagram of the microwave generator of this invention.

Explanation of symbols

11, 101 Second ferromagnetic (metal) layer 12, 102 Nonmagnetic (metal) layer 13, 103 First ferromagnetic (metal) layer 14 Magnetization direction 21 External magnetic field 22 Spin polarized current 23, 51 Opposing end face 31 Upward spin Electron 32 Downward spin electron 33 Equilibrium spin polarization current 41, 71 Scattering direction 42, 72 due to spin-orbit interaction In-plane current (Hall current)
52 Accumulated Charge 61 Loads 81 and 91, Second Ferromagnetic Layer (Magnetic Inversion Layer)
82, 92, non-magnetic layer (spacer)
83, 93, first ferromagnetic layer (magnetization pinned layer)
73, 94 Torque 104 Microwave

Claims (5)

A battery cell comprising at least a first ferromagnetic metal layer, a nonmagnetic metal layer, and a second ferromagnetic metal layer in this order, and a counter electrode for taking out current from opposing end faces of the nonmagnetic metal layer. There,
Each of the first ferromagnetic metal layer and the second ferromagnetic metal layer has a thickness of 1 nm to 200 nm,
The battery cell in which the magnetization directions of the first ferromagnetic metal layer and the second ferromagnetic metal layer change together when a magnetic field is applied.   The battery which laminated | stacked the battery cell of Claim 1 through the insulating layer.   A battery cell according to claim 1 or a battery according to claim 2, and a magnetic field generator capable of applying a magnetic field in a direction perpendicular to the laminated surface of the battery cell or the nonmagnetic metal layer of the battery. Battery system. In-plane size including at least a first ferromagnetic layer, a nonmagnetic layer, and a second ferromagnetic layer in this order, and a counter electrode for flowing a current in a direction parallel to the laminated surface of the nonmagnetic layer A magnetic film cell having a width smaller than the domain wall width;
An alternating current power source capable of applying an alternating current to the magnetic film cell via the counter electrode;
A microwave transmission device comprising a means for synchronizing the frequency of the AC power source and the magnetization vibration period. A magnetic film cell having at least a first ferromagnetic layer, a nonmagnetic layer, and a second ferromagnetic layer in this order and having an in-plane size smaller than the domain wall width;
In the spin-injection magnetization reversal element comprising a first counter electrode provided in a first ferromagnetic layer and a second ferromagnetic layer for flowing a current in a direction perpendicular to the laminated surface of the magnetic film cell, A method for switching the magnetization directions of a first ferromagnetic layer and a second ferromagnetic layer to each other in parallel or antiparallel,
Connecting a variable-polarity power source to each of the first counter electrode and a second counter electrode provided for flowing a current in a direction parallel to the lamination surface of the nonmagnetic layer;
Applying a direct current to the magnetic film cell through the first counter electrode and the second counter electrode using the power source.

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