JP2011002604A - Spin injection type spatial light modulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spin injection type light modulator having high magnetic optical performance and being capable of providing a larger angle of rotation.SOLUTION: The spatial light modulator (SLM) of spin injection type of which the magnetization direction is inverted by spin injection is a laminate element body constituted of a magnetization direction variable layer 20 of which the magnetization direction is inverted by spin injection; a magnetization direction fixed layer 40, of which the magnetization direction is fixed; and a nonmagnetic intermediate layer 30, which is sandwiched between the magnetization direction variable layer and the magnetization direction fixed layer, wherein the magnetization direction variable layer is composed of a magnetic semiconductor material having transparency.

Description

  The present invention relates to a spatial light modulation element, and more particularly to a spatial light modulation element used by changing the magnetization direction by spin injection.

  Conventional spatial light modulators (SLMs) generally use liquid crystals. The principle of controlling the transmission and reflection of light by controlling the alignment and orientation by applying a voltage to liquid crystal molecules is used. This is a technique that has already been widely used, and can be said to be a technique that is widely used in the world including liquid crystal displays.

  However, the SLM using liquid crystal has a drawback in that the response speed is slow due to the rotation of molecules in principle. In order to increase the response speed, there is an OCB (Optically Compensated Bend) structure in which the initial alignment of the liquid crystal molecules is bowed, but the response speed is still only a few msec.

  In addition, since the thickness of the liquid crystal layer is required to be at least several μm, there is a limit to the reduction of the area of the element, and an SLM using liquid crystal requires an element area of about 5 μm × 5 μm, and has a high definition arrangement. It can be said that it is difficult to form.

  On the other hand, an SLM of a type that operates a micromirror manufactured by using a microfabrication technology such as MEMS (Micro Electro Mechanical Systems) has also been proposed. It is difficult to manufacture an element of 10 μm or less. It can also be said that the operation control is complicated.

  In view of this, a new SLM type using magnetization reversal of a magnetic material has been proposed. These use the magneto-optical effect (Faraday effect / Kerr effect) in which transmitted / reflected light is rotated according to the magnetization direction of the magnetic material, and the time required for the magnetization reversal of the magnetic material is generally on the order of nsec. Therefore, it can be said that this is a method that promises high-speed response.

  Among them, the elements disclosed in Japanese Patent Application Laid-Open No. 2008-60906 and Japanese Patent Application Laid-Open No. 2008-83686 are based on spin injection technology (reversing the magnetization direction of a magnetic material by flowing spin-polarized electrons). Technology) is used.

Since an element using magnetization reversal by spin injection has a small area limitation, a fine element of 1 μm ² or less can be produced without any problem. That is, a high-definition element with a high response speed can be manufactured. Note that magnetization reversal by spin injection uses the fact that a torque called spin torque is applied to the magnetization when the angular momentum of the conduction electrons is transferred to the magnetization, and a current in which the electron spin is biased flows to the magnetic material. This is a technique for controlling the magnetization direction according to the circumstances, and is used in, for example, an MRAM.

  Specifically, when electrons move from the magnetization direction fixed layer to the magnetization direction variable layer, the magnetization direction of the variable layer is aligned with the magnetization direction of the fixed layer, and conversely, from the magnetization direction variable layer to the magnetization direction fixed layer. When the electrons move in the direction, the magnetization direction of the magnetization direction variable layer is opposite to the magnetization direction of the magnetization direction fixed layer.

JP 2008-83686 A JP 2008-60906 A JP 2008-64825 A JP 2008-145748 A JP 2008-91842 A JP 2008-177271 A JP 2007-242594 A

  However, the above prior art examples as the prior art have a drawback that the optical rotation angle is small in principle. Therefore, it is strongly desired to propose a device having a novel structure that can improve the drawbacks of the prior art and obtain a larger optical rotation angle.

  Under such circumstances, the present invention has been invented, and an object of the present invention is to provide a spin-injection type light modulation device having high magneto-optical performance so that a larger optical rotation angle can be obtained. is there.

  In order to solve such problems, the present invention is a spin injection spatial light modulator (SLM) whose magnetization direction is reversed by spin injection, and the element is magnetized by spin injection. A multilayer element body having a magnetization direction variable layer whose direction is reversed, a magnetization direction fixed layer whose magnetization direction is fixed, and a nonmagnetic intermediate layer sandwiched between the magnetization direction variable layer and the magnetization direction fixed layer The magnetization direction variable layer is made of a magnetic semiconductor material having transparency.

  Further, as a more preferable aspect of the spin injection type spatial light modulation element of the present invention, the multilayer element body includes a magnetization direction variable layer, a nonmagnetic intermediate layer, and a magnetization direction fixed layer sequentially stacked. The magnetization direction variable layer and the magnetization direction fixed layer are made of a magnetic semiconductor material having transparency.

  As a more preferred embodiment of the spin injection spatial light modulator of the present invention, the nonmagnetic intermediate layer is made of a semiconductor material having transparency.

  Further, as a more preferable aspect of the spin injection type spatial light modulation element of the present invention, the magnetization direction variable layer and the nonmagnetic intermediate layer are configured such that their main components are the same.

Further, as a more preferable aspect of the spin injection type spatial light modulation element of the present invention, the magnetization direction variable layer and the nonmagnetic intermediate layer are configured such that the same main component is TiO ₂ or ZnO. Composed.

As a more preferable aspect of the spin injection spatial light modulator of the present invention, the magnetization direction variable layer is made of Co-added TiO _2, and the nonmagnetic intermediate layer is made of Nb-added TiO _2. .

  As a more preferred aspect of the spin injection spatial light modulator of the present invention, the magnetization direction variable layer is made of Mn-added ZnO, and the nonmagnetic intermediate layer is made of ZnO.

Further, as a more preferable aspect of the spin injection type spatial light modulation element of the present invention, the magnetization direction variable layer, the magnetization direction fixed layer, and the nonmagnetic intermediate layer are each composed of the same main component of TiO ₂ , Or it is comprised so that it may be ZnO.

As a more preferred aspect of the spin injection spatial light modulator of the present invention, the magnetization direction variable layer and the magnetization direction fixed layer are made of Co-added TiO _2, and the nonmagnetic intermediate layer is Nb-added TiO ₂ .

  As a more preferred embodiment of the spin injection spatial light modulator of the present invention, the magnetization direction variable layer and the magnetization direction fixed layer are made of Mn-added ZnO, and the nonmagnetic intermediate layer is made of ZnO. Is done.

  As a more preferred aspect of the spin injection spatial light modulator of the present invention, a lattice matching layer is formed under the magnetization direction variable layer, and the magnetization direction variable layer is located with respect to the lattice matching layer. It is configured to be epitaxially grown.

  As a more preferred aspect of the spin injection spatial light modulator of the present invention, a lattice matching layer is formed under the magnetization direction variable layer, and the magnetization direction variable layer, the nonmagnetic intermediate layer, The magnetization direction fixed layer is formed by epitaxial growth.

  Further, as a more preferable aspect of the spin injection type spatial light modulation element of the present invention, a pair of electrode layers for current application are disposed on both sides of the laminate element body in the lamination direction, and at least light input / output is performed. The electrode layer on which is performed is made of a transparent electrode material.

As a more preferred embodiment of the spin injection spatial light modulator of the present invention, the transparent electrode material is made of indium zinc oxide (IZO), indium tin oxide (ITO), tin oxide. (SnO ₂ ), antimony oxide-tin oxide (ATO), zinc oxide (ZnO), fluorine-doped tin oxide (FTO), and indium oxide (In ₂ O ₃ ).

  Further, as a more preferable aspect of the spin injection type spatial light modulation device of the present invention, between the magnetization direction variable layer and the nonmagnetic intermediate layer and / or between the magnetization direction variable layer and the nonmagnetic intermediate layer. Is configured such that a nonmagnetic layer that does not interfere with spin conduction is inserted.

  The light modulator of the present invention is configured by arranging the above-described spin injection type spatial light modulation elements in a matrix.

  The present invention relates to a spin injection spatial light modulator (SLM) in which the magnetization direction is reversed by spin injection, and the element includes a magnetization direction variable layer whose magnetization direction is reversed by spin injection. A magnetization direction fixed layer having a fixed magnetization direction, and a multilayer element body having a magnetization direction variable layer and a nonmagnetic intermediate layer sandwiched between the magnetization direction fixed layers, the magnetization direction variable layer, Since it is made of a magnetic semiconductor material having transparency, an effect of having extremely high magneto-optical performance is exhibited so that a larger optical rotation angle can be obtained.

FIG. 1 is a schematic cross-sectional view of a spin injection type spatial light modulator of the present invention.

  Hereinafter, the best mode for carrying out a spin injection type spatial light modulator (SLM) in which the magnetization direction is reversed by spin injection according to the present invention will be described in detail.

  FIG. 1 is a schematic cross-sectional view of a preferred embodiment of a spin injection type spatial light modulator of the present invention. In particular, the drawing is a simplified spatial light modulator using a Kerr effect and a Faraday effect. It is a conceptual diagram.

  As shown in FIG. 1, the spin injection type spatial light modulator of the present invention includes a lower electrode layer 11, a lattice matching layer 8 (underlayer in some cases), a magnetization direction variable layer 40, a nonmagnetic intermediate layer from the lower side. It has a columnar (pillar-like) configuration in which the layer 30, the magnetization direction fixed layer 20, the antiferromagnetic layer 10, and the upper electrode layer 15 are sequentially laminated.

  That is, the element is sandwiched between the magnetization direction variable layer 40 whose magnetization direction is reversed by spin injection, the magnetization direction fixed layer 20 whose magnetization direction is fixed, and the magnetization direction variable layer 40 and the magnetization direction fixed layer. And a non-magnetic intermediate layer 30, and a lower electrode layer 11 and an upper electrode layer 15 for applying a current are disposed on both sides of the stack element body 5 in the stacking direction. It takes a form.

  In the element shown in FIG. 1, the magnetization direction fixed layer 20 is disposed above the magnetization direction variable layer 40. In the present application, such an element form is referred to as a “top-type” spatial light modulation element. . On the contrary, the element configuration in which the magnetization direction fixed layer 20 is disposed below the magnetization direction variable layer 40 (so-called substrate side) is referred to as a “bottom type”.

As a technique for increasing the total Kerr rotation angle θ _k of the reflected light, for example, multiple reflection at the magnetic substance interface can be used. In addition, it is desired to construct a system in which the intensity of reflected light is not attenuated while obtaining the effect of multiple reflection. For this purpose, the magnetic layers of the magnetization direction fixed layer 20 and the magnetization direction variable layer 40 are: (1) the magnetic layer itself is transparent to visible light; and (2) conductive for performing spin injection magnetization reversal. It is necessary to select a material that satisfies the following characteristics: (3) having magnetization for performing spin injection magnetization reversal, and (4) having a high magneto-optical effect.

A material that satisfies all these requirements is a transparent magnetic semiconductor that exhibits magnetism at room temperature, such as Co-added TiO ₂ , Fe-added TiO ₂ , and Mn-added ZnO. These will be described in detail later.

  However, it is difficult to form a transparent magnetic semiconductor that satisfies requirements for magnetization and conductivity, and so-called consistency with the base is often important. Therefore, a structure (so-called “top type”) in which the magnetization direction variable layer 40 that does not need to take into consideration the formation of an antiferromagnetic layer for fixing the magnetization direction is formed on the substrate first (so-called “top type”) is provided. It is a preferable aspect that a lattice matching layer is formed as the base of the variable layer 40.

  Thereby, the magnetization direction variable layer 40 formed on the lattice matching layer can be epitaxially grown. Further, by considering the material configuration of the nonmagnetic intermediate layer 30 formed on the magnetization direction variable layer 40 and the magnetization direction fixed layer 20 formed on the nonmagnetic intermediate layer 30, It can be epitaxially grown continuously. These will be described in detail later.

  The optical rotation angle due to the Faraday effect is proportional to the thickness of the layer having the effect, but in general, inversion by spin injection of a magnetic layer that is too thick tends to be difficult. That is, the Faraday effect and the ease of magnetization reversal are in a trade-off relationship. However, if an all-transmissive SLM can be constructed, enhancement of the Faraday effect can be expected by laminating elements in the vertical direction without impairing the ease of magnetization reversal.

  Hereinafter, each component of the present invention will be described in detail.

[Configuration of Magnetization Direction Variable Layer 40]
The magnetization direction variable layer 40 is a magnetic layer whose magnetization direction is not reversed and whose magnetization is easily reversed by spin injection.

  The magnetization direction variable layer 40 in the present invention is composed of a magnetic semiconductor material having transparency (hereinafter also referred to as “transparent magnetic semiconductor material”).

  Here, “having transparency” means “in the light wavelength band of 400 to 700 nm, when the light transmittance of glass is 100%, the average light transmittance of the target film exceeds 80%”, Is defined as

  The magnetization direction variable layer 40 is preferably made of a magnetic semiconductor material that produces a magneto-optical Kerr effect and / or a Faraday effect and has a relatively high degree of polarization.

  The magnetization direction may be either the horizontal direction or the vertical direction. In the illustrated example, the magnetization direction is the horizontal direction.

Examples of the transparent magnetic semiconductor material constituting the magnetization direction variable layer 40 include transparent magnetic semiconductors exhibiting magnetism at room temperature, such as Co-added TiO ₂ , Fe-added TiO ₂ , and Mn-added ZnO.

In the case of Co-added TiO ₂ (hereinafter sometimes simply referred to as “Co-TiO ₂ ”), by adding Co to 1 to 12 atomic% (atomic%) in TiO ₂ in order to impart magnetism and conductivity. Composed.

In the case of Fe-added TiO ₂ (hereinafter sometimes simply referred to as “Fe—TiO ₂ ”), 1 to 10 atomic% (atomic%) of Fe is contained in TiO ₂ in order to impart magnetism and conductivity. Consists of.

  Further, in the case of Mn-added ZnO (hereinafter sometimes simply referred to as “Mn-ZnO”), it is constituted by containing 1 to 12 atomic% (atomic%) of Mn in ZnO in order to impart magnetism and conductivity. Is done.

  The thickness of the magnetization direction variable layer 40 is about 2 to 20 nm. As a deposition method, for example, a molecular beam epitaxy method (MBE method), a sputtering method, or the like can be used.

  In a preferred embodiment of the present invention, in the so-called “top type” element configuration in which the magnetization direction variable layer 40 is provided on the substrate side (lower side), the underlying layer of the layer 40 can be selected by selecting the material of the magnetization direction variable layer 40. In some cases, it is extremely preferable to provide a desired lattice matching layer from the viewpoint of improving optical characteristics. Furthermore, depending on the material selection of the magnetization direction variable layer 40, the material selection of the nonmagnetic intermediate layer 30 and the magnetization direction fixed layer 20 formed thereon may be important. The relationship between these layers will be described in detail later.

[Configuration of magnetization direction fixed layer 20]
The magnetization direction fixed layer 20 is a layer whose magnetization direction is fixed, and it is generally preferable to use a material having a high spin polarizability. The magnetization direction may be either the horizontal direction or the vertical direction. In the illustrated example, the magnetization direction is the horizontal direction. As shown in FIG. 1, when the magnetization direction of the magnetization direction fixed layer 20 is horizontal, the magnetization direction of the magnetization direction variable layer 40 is also horizontal. On the contrary, when the magnetization direction of the magnetization direction fixed layer 20 is vertical, the magnetization direction of the magnetization direction variable layer 40 is also vertical.

  The magnetization direction fixed layer 20 is preferably made of a magnetic semiconductor material having transparency. By doing so, it is possible to construct an ideal system in which the intensity of reflected light is not attenuated while obtaining the effect of multiple reflection.

  As a preferred embodiment, the transparent magnetic semiconductor material constituting the magnetization direction fixed layer 20 can be the same material as the magnetization direction variable layer 40 described above. The thickness of the magnetic layer may be set to the same level. As a deposition method, for example, a molecular beam epitaxy method (MBE method), a sputtering method, or the like can be used.

  The magnetization direction fixed layer 20 is preferably made of the transparent magnetic semiconductor material as described above. Other materials include Co, Fe, Ni and their alloys, amorphous magnetic materials such as CoFeB and CoZrTa, rare earth amorphous alloys such as TbFeCo and GdFeCo, Heusler alloys such as CoMnSi and CoMnGe, Co / Pt, Co / An artificial lattice such as Ni can also be used. However, in the case of other materials, there is a tendency that the optical characteristics are slightly lowered as compared with the case where a transparent magnetic semiconductor material is used.

  In general, as shown in FIG. 1, in order to fix the magnetization of the magnetization direction fixed layer 20, for example, the spin fixed layer 10 made of an antiferromagnetic material is formed in a bonded state.

  Examples of the antiferromagnetic material constituting the spin fixed layer 10 include an element M ′ composed of at least one selected from the group of Pt, Ru, Rh, Pd, Ni, Cu, Ir, Cr, and Fe. And an antiferromagnetic material containing Mn. The Mn content is preferably 35 to 95 atomic%. Among the antiferromagnetic materials are (1) a non-heat treated antiferromagnetic material that exhibits antiferromagnetism without inducing heat treatment and induces an exchange coupling magnetic field with the ferromagnetic material, and (2) by heat treatment. There is a heat-treated antiferromagnetic material that exhibits antiferromagnetism. In the present invention, either type (1) or (2) may be used. Examples of the non-heat treatment type antiferromagnetic material include RuRhMn, FeMn, IrMn and the like. Examples of the heat-treated antiferromagnetic material include PtMn, NiMn, and PtRhMn.

  The thickness of the spin fixed layer 10 is about 3 to 10 nm.

[Configuration of Nonmagnetic Intermediate Layer 30]
As shown in FIG. 1, the nonmagnetic intermediate layer 30 is configured to be sandwiched between the magnetization direction fixed layer 20 and the magnetization direction variable layer 40.

  Here, “sandwiched” means (1) a state in which both planes of the nonmagnetic intermediate layer 30 are in direct contact with the magnetization direction fixed layer 20 and the magnetization direction variable layer 40, respectively, and (2) nonmagneticity. This includes both the state in which both planes of the intermediate layer 30 are in indirect contact with each other between the magnetization direction fixed layer 20 and the magnetization direction variable layer 40 with an arbitrary layer interposed. However, in the case of indirect contact, it is limited to the case where the operational effects of the present invention are manifested without interfering with the operational effects of the present invention even if any layer is interposed. As an arbitrary layer interposed, a nonmagnetic layer (for example, Cu, Zn, Au, Ag) that does not hinder spin conduction can be used.

The nonmagnetic intermediate layer 30 in the present invention, Cu, Zn, Ag, and a nonmagnetic material such as _{Au, ZnO, TiO 2, In 2} O 3, SnO 2, GaN, GaP, GaAs, GaSb, AlN, AlP, A semiconductor material mainly containing InP, InAs, InSb, ZnS, ZnSe, ZnTe, SiC, or NiO can be used. Among these, it is particularly desirable to be made of a transparent material.

In particular, the material for the nonmagnetic intermediate layer 30 can be selected according to the following procedure while taking into account the specific transparent magnetic semiconductor materials selected for the magnetization direction variable layer 40 and the magnetization direction fixed layer 20. desirable. That is,
(1) It is desirable that the magnetization direction variable layer 40 and the nonmagnetic intermediate layer 30 have the same main component, and are configured so as to be distinguished by an additive or the like.

  Hereinafter, specific examples will be described.

(1-i) The magnetization direction variable layer 40 is a Co-added TiO ₂ (Co—TiO ₂ ) transparent magnetic semiconductor, and the nonmagnetic intermediate layer 30 is Nb-added TiO ₂ (Nb—TiO ₂ ). Nb—TiO ₂ is a semiconductor having transparency.

The main component is TiO ₂ and is the same in both layers. In this case, the Co addition amount (content) in the magnetization direction variable layer 40 is as described above, and the Nb addition amount (content) in the nonmagnetic intermediate layer 30 is 1 to 10 atomic% (atomic%).

The Co addition amount and the Nb addition amount are determined from the viewpoints of magnetism, conductivity, and visible light transmittance. However, since the lattice constant of TiO _{2 serving as} a base does not change greatly, the magnetization direction variable layer 40-nonmagnetic The intermediate layer 30 can be stacked by epitaxial growth.

  (1-ii) The magnetization direction variable layer 40 is made of Mn-doped ZnO (Mn—ZnO) transparent magnetic semiconductor, and the nonmagnetic intermediate layer 30 is made of ZnO. ZnO is a semiconductor having transparency.

  The main component is ZnO and is the same in both layers. In this case, the Mn addition amount (content) in the magnetization direction variable layer 40 is as described above.

  The amount of Mn added is determined from the viewpoints of magnetism, conductivity, and visible light transmission, but since the lattice constant of ZnO serving as a base does not change greatly, the magnetization direction variable layer 40-the nonmagnetic intermediate layer 30 are Stacking by epitaxial growth is possible.

(1-iii) The magnetization direction variable layer 40 is made of a Fe-doped TiO ₂ (Fe—TiO ₂ ) transparent magnetic semiconductor, and the nonmagnetic intermediate layer 30 is made of Nb-doped TiO ₂ (Nb—TiO ₂ ). Nb—TiO ₂ is a semiconductor having transparency.

The main component is TiO ₂ and is the same in both layers. In this case, the addition amount (content) of Fe in the magnetization direction variable layer 40 is as described above.

The addition amount of Fe and the addition amount of Nb are determined from the viewpoints of magnetism, electrical conductivity, and visible light transmittance. However, since the lattice constant of TiO _{2 serving as} a base does not change greatly, the magnetization direction variable layer 40—nonmagnetic The intermediate layer 30 can be stacked by epitaxial growth.

(2) The magnetization direction variable layer 40, the nonmagnetic intermediate layer 30, and the magnetization direction fixed layer 20 are configured such that the main components are the same, and the magnetic layers 20, 40 and the intermediate layer 30 are configured. Is preferably configured to be distinguished by an additive or the like.

  Hereinafter, specific examples will be described.

(2-i) The magnetization direction variable layer 40 and the magnetization direction fixed layer 20 are made of Co-added TiO ₂ (Co—TiO ₂ ) transparent magnetic semiconductor, and the nonmagnetic intermediate layer 30 is made of Nb-added TiO ₂ (Nb—TiO ₂ ). To do. Nb—TiO ₂ is a semiconductor having transparency.

The main component is TiO ₂ and is the same. In this case, the Co addition amount (content) in the magnetization direction variable layer 40 and the magnetization direction fixed layer 20 is as described above.

The Co addition amount and the Nb addition amount are determined from the viewpoints of magnetism, conductivity, and visible light transmittance. However, since the lattice constant of TiO _{2 serving as} a base does not change greatly, the magnetization direction variable layer 40-nonmagnetic The intermediate layer 30 and the magnetization direction fixed layer 20 can be stacked by epitaxial growth.

  (2-ii) The magnetization direction variable layer 40 and the magnetization direction fixed layer 20 are Mn-doped ZnO (Mn-ZnO) transparent magnetic semiconductors, and the nonmagnetic intermediate layer 30 is ZnO. ZnO is a semiconductor having transparency.

  The main component is ZnO and is the same. In this case, the amount of Mn added (content) in the magnetization direction variable layer 40 and the magnetization direction fixed layer 20 is as described above. The amount of Mn added is determined from the viewpoints of magnetism, conductivity, and visible light transmission, but since the lattice constant of ZnO as a base does not change greatly, the magnetization direction variable layer 40-the nonmagnetic intermediate layer 30-the magnetization The direction fixed layer 20 can be formed by epitaxial growth.

(2-iii) The magnetization direction variable layer 40 and the magnetization direction fixed layer 20 are made of a Fe-doped TiO ₂ (Fe—TiO ₂ ) transparent magnetic semiconductor, and the nonmagnetic intermediate layer 30 is made of Nb-doped TiO ₂ (Nb—TiO ₂ ). To do. Nb—TiO ₂ is a semiconductor having transparency.

The main component is TiO ₂ and is the same. In this case, the Fe addition amount (content) in the magnetization direction variable layer 40 and the magnetization direction fixed layer 20 is as described above.

The addition amount of Fe and the addition amount of Nb are determined from the viewpoints of magnetism, electrical conductivity, and visible light transmittance. However, since the lattice constant of TiO _{2 serving as} a base does not change greatly, the magnetization direction variable layer 40—nonmagnetic The intermediate layer 30 and the magnetization direction fixed layer 20 can be stacked by epitaxial growth.

When the magnetization direction variable layer 40 is composed of Co—TiO ₂ , Fe—TiO _2, or the like, the magnetization direction variable layer 40 is used as a base so that the magnetization direction variable layer 40 can be epitaxially grown on the base. The following lattice matching layer 8 is preferably formed.

[Description of Lattice Matching Layer 8]
The lattice matching layer 8 is, for example, a two-layer stack (Ta / NiFe-N) in which a NiFe layer (NiFe-N) added with nitrogen is formed on an amorphous layer made of Ta having a thickness of about 3 nm. It is mentioned as a suitable example. The amount of N added is 0.5 to 25 atomic% (atomic%).

The Ta layer is amorphous and is formed once to cancel crystallinity. Note that the layer is not limited to the Ta layer as long as the crystallinity can be canceled once. The NiFe—N layer is for forming a (001) -oriented crystal, and the magnetization direction variable layer 40 made of Co—TiO ₂ , Fe—TiO _2, etc. formed thereon is epitaxial ( (001) orientation) has been confirmed to grow. For details, refer to the experimental examples described later.

  When the ZnO-based magnetization direction variable layer 40 is used, ZnO has a strong polarity and easily forms a (001) -oriented crystal with high crystallinity regardless of the material of the base. Therefore, the material for the base is not particularly limited. Therefore, when the ZnO-based magnetization direction variable layer 40 is used, for example, a Ta layer having a thickness of 1 nm and a thickness of about 2 nm are used instead of the lattice matching layer 8 without providing the lattice matching layer 8 described above. It is sufficient to provide a base layer made of a two-layered laminate of Re layers.

[Lower electrode layer 11, upper electrode layer 15]
The lower electrode layer 11 and the upper electrode layer 15 are formed on both sides in the stacking direction of the multilayer body 5 for current application. The lower electrode layer 11 and / or the upper electrode layer 15 are made of a transparent electrode material so that light can enter and exit. In the case where light enters and exits only from one electrode layer, only the electrode layer may be made of a transparent electrode material.

Specific examples of transparent electrode materials include indium zinc oxide (IZO), indium tin oxide (ITO), tin oxide (SnO ₂ ), antimony-doped tin oxide (ATO), and zinc oxide. (ZnO), fluorine-doped tin oxide (FTO), indium oxide (In ₂ O ₃ ), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (AZO), niobium-doped zinc oxide (NTO), and the like.

  In FIG. 1, between the upper electrode layer 15 and the antiferromagnetic layer 10, Al, Ti, Cr, Cu, Zn, Zr, Nb, Mo, Ru, Rh, Pd, Ag, In, Sn, Hf, Cap layers such as Ta, W, Re, Ir, Pt, Au, Pb, Bi, and alloys thereof can be provided.

1. Description of Action of Spin-Injection Type Spatial Light Modulation Element In FIG. 1, the magnetization direction of the magnetization direction fixed layer 20 is fixed in the horizontal direction and in the right direction (arrow 20a). The magnetization direction of the magnetization direction variable layer 40 is aligned in the same direction as the magnetization direction of the magnetization direction fixed layer 20 or in the opposite opposite direction depending on the spin injection specifications.

  That is, when a current is applied from the lower electrode layer 11 to the upper electrode layer 15 and electrons move from the magnetization direction fixed layer 20 toward the magnetization direction variable layer 40, the magnetization direction of the magnetization direction variable layer 40 changes to the magnetization direction fixed layer 20. The magnetization direction is aligned horizontally and rightward.

  On the contrary, when a current is applied from the upper electrode layer 15 to the lower electrode layer 11 and electrons move from the magnetization direction variable layer 40 toward the magnetization direction fixed layer 20, the magnetization direction of the magnetization direction variable layer 40 changes to the magnetization direction. The magnetization direction is opposite to the magnetization direction of the direction fixed layer 20, and the magnetization direction is horizontal and leftward.

Depending on the case where the magnetization directions of both the magnetization direction variable layer 40 and the magnetization direction fixed layer 20 are aligned and in the same direction, and the case where the magnetization directions of both are opposite and in the opposite direction, reflected light respectively. If the total Kerr rotation angle is set to θ _k , two types of polarized light having a polarization angle of + θ _k and −θ _k can be obtained depending on the magnetization direction of the magnetic material, and light modulation (optical rotation) can be realized. . That is, when the magnetization direction of the magnetization direction variable layer 40 is reversed by spin injection, the polarization axis of light passing through or reflecting the region is observed in the opposite direction to the polarization axis of the magnetization direction variable layer 40 before the reversal. The

  As described above, the spin-injection type spatial light modulation element in the present invention uses rotation of the polarization direction of light by reversal of the magnetization direction, and thus various conventional elements (for example, alignment of liquid crystal molecules, movement / rotation of particles) Or an element that performs control such as angular rotation of the pixel mirror), the operation speed is high, and an operation speed of about 10 to 50 nsec can be obtained.

  In addition, the spin injection type spatial light modulator according to the present invention has a simple structure. That is, no active element (TFT) for maintaining operation like a liquid crystal element is required, and no mechanical operation such as a micromirror is involved. Furthermore, the film thickness of the element for ensuring contrast can be made thinner than that of the liquid crystal element.

  The spin-injection type spatial light modulator according to the present invention has a size of at least submicron or less if it is manufactured using the current microfabrication technology in the form shown in FIG. 1 and forming one pixel of the light modulator. High-definition processing is possible.

Description of development to optical modulator The optical modulator can be formed by arranging the elements in a matrix so that one of the spin injection type spatial light modulating elements in the present invention forms one pixel. it can.

  The optical modulator includes a spin injection spatial light modulator disposed in each of a plurality of pixels arranged in a matrix, and polarization of incident light to the spin injection spatial light modulator by reversal of the magnetization direction. And a polarizing means (for example, a polarizing plate) for detecting a change in direction. Further, a pixel selection electrode for selecting an arbitrary pixel is connected to each of the spin injection type spatial light modulation elements, and the magnetization direction is inverted through the pixel selection electrode.

  A spin injection type spatial light modulation element is an element such as a columnar (pillar) arranged for each pixel (see FIG. 1), and adjacent spin injection type spatial light modulation elements are electrically connected to each other. And magnetically insulated.

  Further, the spin injection spatial light modulator may be configured such that three-color light corresponding to RGB is incident in a time division manner as incident light.

  Further, a shutter may be further provided between the spin injection spatial light modulator and the polarization means so that the polarization angle of incident light can be varied in a time-sharing manner.

  Hereinafter, specific experimental examples relating to the spin injection type spatial light modulation element of the present invention will be shown, and the present invention will be described in more detail. As specific experimental examples, Samples 1 and 2 as comparative examples and Samples 3 through 6 according to the present invention were produced as shown below. In addition, in the following Table 1, the laminated structures of Samples 3 to 6 which are the elements of the present invention are shown as representative laminated structures of the elements so that the laminated structure of the elements can be easily recognized.

[ Production of Sample 1 (Comparative Example) ]
As a sample 1, a spatial light modulation element sample of a comparative example made of “non-transparent” was produced as follows.

  That is, a base layer made of Al having a thickness of 3.0 nm is formed on the lower electrode layer 11 made of Cu having a thickness of 500 nm, and an antiferromagnetic material made of IrMn having a thickness of 6.0 nm is formed on the base layer. A layer (spin pinned layer 10) was formed, and a magnetization direction fixed layer 20 made of CoFe having a thickness of 10.0 nm was formed on the antiferromagnetic layer. The antiferromagnetic layer made of IrMn is provided to fix the magnetization of the magnetization direction fixed layer 20.

  A nonmagnetic intermediate layer 30 made of Cu having a thickness of 1.5 nm was formed on the magnetization direction fixed layer 20, and the magnetization direction variable layer 40 was formed on the nonmagnetic intermediate layer 30.

  The magnetization direction variable layer 40 was a two-layer laminate in which NiFe having a thickness of 5.0 nm was formed on CoFe having a thickness of 5.0 nm.

  On the magnetization direction variable layer 40, a cap layer made of a two-layered laminate of Ru having a thickness of 1.0 nm and Ta having a thickness of 2.0 nm was formed.

  The laminated film thus formed is processed into a 320 × 320 nm square pillar shape, the side surface is covered with an insulating layer made of alumina having a thickness of 20.0 nm, the cap layer is removed by etching, and then the upper electrode layer (ITO Sample 500 was prepared by forming a thickness of 500 nm) on top.

  The sample was a so-called bottom type sample in which the magnetization direction fixed layer 20 is located below the magnetization direction variable layer 40.

[ Production of Sample 2 (Comparative Example) ]
As a sample 2, a spatial light modulation element sample of a comparative example made of “non-transparent” was prepared as follows.

  That is, a base layer made of Al having a thickness of 3.0 nm was formed on the lower electrode layer 11 made of Cu having a thickness of 500 nm, and the magnetization direction variable layer 40 was formed on the base layer.

  The magnetization direction variable layer 40 was a two-layer laminate in which NiFe having a thickness of 5.0 nm was formed on CoFe having a thickness of 5.0 nm.

  A nonmagnetic intermediate layer 30 made of Cu having a thickness of 1.5 nm is formed on the magnetization direction variable layer 40, and the magnetization direction is fixed on the nonmagnetic intermediate layer 30 made of CoFe having a thickness of 10.0 nm. A layer 20 was formed, and an antiferromagnetic layer (spin pinned layer 10) made of IrMn having a thickness of 6.0 nm was formed on the magnetization direction fixed layer 20. The antiferromagnetic layer made of IrMn is provided to fix the magnetization of the magnetization direction fixed layer 20.

  On this antiferromagnetic layer, a cap layer made of a two-layered laminate of Ru having a thickness of 1.0 nm and Ta having a thickness of 2.0 nm was formed.

  The laminated film thus formed is processed into a 320 × 320 nm square pillar shape, the side surface is covered with an insulating layer made of alumina having a thickness of 20.0 nm, the cap layer is removed by etching, and then the upper electrode layer (ITO Sample 2 was prepared by forming a thickness of 500 nm) on top.

  The sample was a so-called top type sample in which the magnetization direction fixed layer 20 is positioned above the magnetization direction variable layer 40.

[ Production of Sample 3 (Invention) ]
In the following manner, a “transparent” spatial light modulation element sample (present invention) in which at least the magnetization direction variable layer 40 is made of a transparent magnetic semiconductor was prepared as Sample 3.

  That is, on the lower electrode layer 11 made of Cu having a thickness of 500 nm, Ta lattice having a thickness of 3.0 nm and NiFe—N having a thickness of 5.0 nm are sequentially laminated to form a lattice matching layer 8 made of a two-layer laminate. Formed. A magnetization direction variable layer 40 was formed on the lattice matching layer 8. NiFe—N that bears one layer of the lattice matching layer 8 was formed by adding 10 atomic% (atomic%) of N to NiFe.

The lattice matching layer 8 was inserted in order to make the TiO ₂ -based material formed thereon into an anatase structure. TiO ₂ can adopt an anatase structure, a rutile structure, or a brookite structure at normal temperature under atmospheric pressure, and among these, the anatase structure can reduce the resistivity most. Use of the anatase structure TiO ₂ lowers the resistivity and can reduce power consumption.

The magnetization direction variable layer 40 was made of Co—TiO ₂ having a thickness of 5.0 nm. Co—TiO ₂ was constituted by adding 10 atomic% (atomic%) of Co to TiO ₂ in order to impart magnetism and conductivity.

A nonmagnetic intermediate layer 30 made of Nb—TiO ₂ having a thickness of 1.5 nm was formed on the magnetization direction variable layer 40. Nb—TiO ₂ was constituted by adding 5 atomic% (atomic%) of Nb to TiO ₂ (which leads to a reduction in power consumption) in order to lower the resistance.

On the nonmagnetic intermediate layer 30, a magnetization direction fixed layer 20 made of Co—TiO ₂ having a thickness of 10.0 nm was formed. Co—TiO ₂ was constituted by adding 10 atomic% (atomic%) of Co to TiO ₂ in order to impart magnetism and conductivity.

  On the magnetization direction fixed layer 20, an antiferromagnetic layer (spin pinned layer 10) made of IrMn having a thickness of 6.0 nm was formed. The antiferromagnetic layer made of IrMn is provided to fix the magnetization of the magnetization direction fixed layer 20.

  On this antiferromagnetic layer, a cap layer made of a two-layered laminate of Ru having a thickness of 1.0 nm and Ta having a thickness of 2.0 nm was formed.

  The laminated film thus formed is processed into a 320 × 320 nm square pillar shape, the side surface is covered with an insulating layer made of alumina having a thickness of 20.0 nm, the cap layer is removed by etching, and then the upper electrode layer (ITO Sample 3 was produced by forming a thickness of 500 nm) on top.

  The sample was a so-called top type sample in which the magnetization direction fixed layer 20 is positioned above the magnetization direction variable layer 40.

[ Production of Sample 4 (Invention) ]
In the following manner, as a sample 4, a “transparent” spatial light modulation element sample (the present invention) in which at least the magnetization direction variable layer 40 is made of a transparent magnetic semiconductor was produced.

  That is, on the lower electrode layer 11 made of Cu having a thickness of 500 nm, Ta lattice having a thickness of 3.0 nm and NiFe—N having a thickness of 5.0 nm are sequentially laminated to form a lattice matching layer made of a two-layer laminate. did. A magnetization direction variable layer 40 was formed on the lattice matching layer. NiFe—N that bears one layer of the lattice matching layer was formed by adding 10 atomic% (atomic%) of N to NiFe.

The lattice matching layer was inserted in order to make the TiO ₂ -based material formed thereon into an anatase structure. TiO ₂ can adopt an anatase structure, a rutile structure, or a brookite structure at normal temperature under atmospheric pressure, and among these, the anatase structure can reduce the resistivity most. Use of the anatase structure TiO ₂ lowers the resistivity and can reduce power consumption.

The magnetization direction variable layer 40 was made of Co—TiO ₂ having a thickness of 5.0 nm. Co—TiO ₂ was constituted by adding 10 atomic% (atomic%) of Co to TiO ₂ in order to impart magnetism and conductivity.

  A nonmagnetic intermediate layer 30 made of Cu having a thickness of 1.5 nm was formed on the magnetization direction variable layer 40.

  A magnetization direction fixed layer 20 made of CoFe having a thickness of 10.0 nm is formed on the nonmagnetic intermediate layer 30, and an antiferromagnetic layer made of IrMn having a thickness of 6.0 nm is formed on the magnetization direction fixed layer 20. (Spin fixed layer 10) was formed. The antiferromagnetic layer made of IrMn is provided to fix the magnetization of the magnetization direction fixed layer 20.

  On this antiferromagnetic layer, a cap layer made of a two-layered laminate of Ru having a thickness of 1.0 nm and Ta having a thickness of 2.0 nm was formed.

  The laminated film thus formed is processed into a 320 × 320 nm square pillar shape, the side surface is covered with an insulating layer made of alumina having a thickness of 20.0 nm, the cap layer is removed by etching, and then the upper electrode layer (ITO Sample 4 was prepared by forming a thickness of 500 nm) on top.

  The sample was a so-called top type sample in which the magnetization direction fixed layer 20 is positioned above the magnetization direction variable layer 40.

[ Production of Sample 5 (Invention) ]
In the following manner, as a sample 5, a transparent spatial light modulation element sample (the present invention) in which at least the magnetization direction variable layer 40 is made of a transparent magnetic semiconductor was produced.

  That is, on the lower electrode layer 11 made of Cu having a thickness of 500 nm, Ta having a thickness of 1.0 nm and Ru having a thickness of 2.0 nm were sequentially laminated to form a base layer made of a two-layer laminate. A magnetization direction variable layer 40 was formed on the underlayer.

  The magnetization direction variable layer 40 was Mn—ZnO having a thickness of 5.0 nm. Mn—ZnO was constituted by adding 3 atomic% (atomic%) of Mn to ZnO in order to impart magnetism and conductivity. Note that ZnO has a strong polarity, and a (001) -oriented highly crystalline ZnO film can be easily obtained regardless of the composition of the underlying layer formed thereunder.

  A nonmagnetic intermediate layer 30 made of ZnO having a thickness of 1.5 nm was formed on the magnetization direction variable layer 40.

  A magnetization direction fixed layer 20 made of Mn—ZnO having a thickness of 10.0 nm is formed on the nonmagnetic intermediate layer 30, and an antiferroelectric strength made of IrMn having a thickness of 6.0 nm is formed on the magnetization direction fixed layer 20. A magnetic layer (spin pinned layer 10) was formed. The antiferromagnetic layer made of IrMn is provided to fix the magnetization of the magnetization direction fixed layer 20.

  On this antiferromagnetic layer, a cap layer made of a two-layered laminate of Ru having a thickness of 1.0 nm and Ta having a thickness of 2.0 nm was formed.

  The laminated film thus formed is processed into a 320 × 320 nm square pillar shape, the side surface is covered with an insulating layer made of alumina having a thickness of 20.0 nm, the cap layer is removed by etching, and then the upper electrode layer (ITO Sample 5 was prepared by forming a thickness of 500 nm) on top.

  The sample was a so-called top type sample in which the magnetization direction fixed layer 20 is positioned above the magnetization direction variable layer 40.

[ Production of Sample 6 (Invention) ]
A “transparent” spatial light modulation element sample (present invention) was prepared as Sample 6 in the following manner.

  That is, a base layer made of Ta having a thickness of 3.0 nm was formed on the lower electrode layer 11 made of Cu having a thickness of 500 nm. A magnetization direction variable layer 40 was formed on the underlayer.

The magnetization direction variable layer 40 was made of Co—TiO ₂ having a thickness of 5.0 nm. Co—TiO ₂ was constituted by adding 10 atomic% (atomic%) of Co to TiO ₂ in order to impart magnetism and conductivity.

A nonmagnetic intermediate layer 30 made of Nb—TiO ₂ having a thickness of 1.5 nm was formed on the magnetization direction variable layer 40. Nb—TiO ₂ was constituted by adding 5 atomic% (atomic%) of Nb to TiO ₂ (which leads to a reduction in power consumption) in order to lower the resistance.

On the nonmagnetic intermediate layer 30, a magnetization direction fixed layer 20 made of Co—TiO ₂ having a thickness of 10.0 nm was formed. Co—TiO ₂ was constituted by adding 10 atomic% (atomic%) of Co to TiO ₂ in order to impart magnetism and conductivity.

  An antiferromagnetic layer (spin pinned layer 10) made of IrMn having a thickness of 6.0 nm was formed on the magnetization direction fixed layer 20. The antiferromagnetic layer made of IrMn is provided to fix the magnetization of the magnetization direction fixed layer 20.

  On this antiferromagnetic layer, a cap layer made of a two-layered laminate of Ru having a thickness of 1.0 nm and Ta having a thickness of 2.0 nm was formed.

  The laminated film thus formed is processed into a 320 × 320 nm square pillar shape, the side surface is covered with an insulating layer made of alumina having a thickness of 20.0 nm, the cap layer is removed by etching, and then the upper electrode layer (ITO Sample 6 was produced by forming a thickness of 500 nm) on top.

  The sample is a so-called top type sample in which the magnetization direction fixed layer 20 is positioned above the magnetization direction variable layer 40.

  This sample 6 can be said to be produced in order to confirm the effect of the crystal orientation layer of the sample 3.

( Evaluation of sample optical properties )
With respect to Samples 1 to 8, a 633 nm laser was used, and the device was subjected to spin injection magnetization reversal by energizing from −100 mA to +100 mA, further energizing from +100 mA to −100 mA. The reflectivity and the Kerr rotation angle θk in each of the state in which the magnetization directions of the magnetic layers were parallel and the state in which the two magnetic layers were antiparallel were measured.

  These measured values and the magneto-optical performance index calculated using these measured values are shown in Table 2 below.

  From the results shown in Table 2, the following matters are considered.

< Consideration between Sample 1 (Comparative Example) and Sample 2 (Comparative Example) >
Samples 1 and 2 are both non-transparent comparative samples. However, by comparing Samples 1 and 2, the magnetization direction variable layer is disposed on the lower substrate side (the magnetization direction fixed layer is positioned on the top side). This type is called the “top type”), and the probability of escape of polarized light is reduced, and the observed Kerr rotation angle is attenuated.

< Consideration between Samples 3 and 5 (all of the present invention) and Sample 2 (Comparative Example) >
Samples 3 and 5 using the same top-type contrast and transparent magnetic semiconductors for both the magnetization direction variable layer and the magnetization direction fixed layer are both more reflective and Kerr rotation angles than sample 2 (comparative example). It showed a large value and an excellent magneto-optical figure of merit.

  This is due to the fact that the attenuation coefficient is close to zero (meaning that it is transparent to visible light), so the absorption of light is weak and the probability of escape of polarized light is high. I think that the.

  In addition, regarding the sample 3 in which the lattice adjustment layer is disposed on the base, the TEM indicates that the three layers of the magnetization direction variable layer 20, the nonmagnetic intermediate layer 30, and the magnetization direction fixed layer 40 are epitaxially grown with the same lattice. This can be confirmed by cross-sectional analysis.

  For sample 5, although the lattice adjustment layer is not disposed on the underlayer, ZnO has a strong polarity and a (001) -oriented ZnO film having a high crystallinity regardless of the composition of the underlayer formed thereunder. Since it can be easily obtained, the three layers of ZnO-based magnetization direction variable layer 20, nonmagnetic intermediate layer 30, and magnetization direction fixed layer 40 are epitaxially grown with a uniform lattice. I was able to confirm.

< Consideration of Comparison between Sample 3 (Invention) and Sample 4 (Invention) >
Sample 4 using a transparent magnetic semiconductor for the magnetization direction variable layer and a metal magnetic material for the magnetization direction fixed layer has a lower magneto-optical performance than Sample 3 using a transparent magnetic semiconductor for the magnetization direction fixed layer. The index is shown.

  In addition, it was confirmed by the cross-sectional analysis by TEM that the sample 4 was epitaxially grown with a uniform lattice up to the magnetization direction variable layer 20.

< Consideration between Sample 4 (present invention) and Sample 2 (Comparative Example) >
On the other hand, it is clear from the comparison with Sample 2 that Sample 4 exhibits the effect of applying the transparent magnetic semiconductor whose orientation is controlled even in the magnetization direction variable layer.

  As described above, it was confirmed by the cross-sectional analysis by TEM that the sample 4 was epitaxially grown up to the magnetization direction variable layer 20 with a uniform lattice.

< Consideration of Comparison between Sample 3 (Invention) and Sample 6 (Invention) (Effect of Presence or absence of Lattice Adjustment Layer) >
In addition, by comparing the sample 3 and the sample 6, the influence of the crystallinity of the TiO ₂ material due to the presence or absence of the lattice adjustment layer was evaluated. Although it can be said that the reflectance is not greatly different between the two, the Kerr rotation angle showed a large value in the sample 3 using the crystallized TiO ₂ . As a result, there was a difference in the magneto-optical performance index, and it became clear that the optical characteristics could be improved by increasing the crystallinity of the transparent magnetic semiconductor layer.

  In the sample 3 of the present invention, when the top type is changed to the bottom type, the IrMn antiferromagnetic layer is formed on the lattice adjustment layer, so that it is formed following the IrMn antiferromagnetic layer. Since none of the magnetization direction fixed layer 40, the nonmagnetic intermediate layer 30, and the magnetization direction variable layer 20 is epitaxially grown, the optical characteristics cannot be improved. In addition, since the attenuation coefficient of IrMn is large, the optical characteristics cannot be improved.

  In the sample 4 of the present invention, when the top type is changed to the bottom type, the optical characteristics cannot be improved because the attenuation coefficient of IrMn is large.

  In the sample 5 of the present invention, when the top type is changed to the bottom type, the optical characteristics cannot be improved because the attenuation coefficient of IrMn is large.

  In the sample 6 of the present invention, when the top type is changed to the bottom type, the optical characteristics cannot be improved because the attenuation coefficient of IrMn is large.

The effect of the present invention is clear from the above experimental results.
That is, the present invention is a spin injection type spatial light modulator (SLM) whose magnetization direction is reversed by spin injection, and the element has a variable magnetization direction whose magnetization direction is reversed by spin injection. A layered body having a layer, a magnetization direction fixed layer whose magnetization direction is fixed, and a magnetization direction variable layer and a nonmagnetic intermediate layer sandwiched between the magnetization direction fixed layers, the magnetization direction variable layer Is composed of a magnetic semiconductor material having transparency, so that an effect of having extremely high magneto-optical performance is exhibited in order to obtain a larger optical rotation angle.

  INDUSTRIAL APPLICABILITY The present invention can be used in the technical field of spatial light modulation elements that are used by changing the magnetization direction by spin injection, for example, the stereoscopic image field.

DESCRIPTION OF SYMBOLS 5 ... Laminated body 8 ... Lattice matching layer 10 ... Spin pinned layer 11 ... Lower electrode layer 15 ... Upper electrode layer 20 ... Magnetization direction fixed layer 30 ... Nonmagnetic intermediate layer 40 ... Magnetization direction variable layer

Claims (16)

A spin injection spatial light modulator (SLM) in which the magnetization direction is reversed by spin injection,
The element is
A magnetization direction variable layer whose magnetization direction is reversed by spin injection, a magnetization direction fixed layer whose magnetization direction is fixed, and a nonmagnetic intermediate layer sandwiched between the magnetization direction variable layer and the magnetization direction fixed layer It consists of a multilayer element body,
The spin injection type spatial light modulator, wherein the magnetization direction variable layer is made of a magnetic semiconductor material having transparency. The laminate element body is formed by sequentially laminating a magnetization direction variable layer, a nonmagnetic intermediate layer, and a magnetization direction fixed layer,
The spin injection spatial light modulation element according to claim 1, wherein the magnetization direction variable layer and the magnetization direction fixed layer are made of a magnetic semiconductor material having transparency.   The spin injection spatial light modulator according to claim 2, wherein the nonmagnetic intermediate layer is made of a semiconductor material having transparency.   The spin injection spatial light modulator according to claim 3, wherein the magnetization direction variable layer and the nonmagnetic intermediate layer have the same main component. The spin injection spatial light modulator according to claim 4, wherein the same main component of each of the magnetization direction variable layer and the nonmagnetic intermediate layer is TiO ₂ or ZnO. The magnetization direction variable layer is made of Co-added TiO ₂ ,
The spin injection spatial light modulator according to claim 5, wherein the nonmagnetic intermediate layer is made of Nb-added TiO ₂ . The magnetization direction variable layer is made of Mn-added ZnO,
The spin injection spatial light modulator according to claim 5, wherein the nonmagnetic intermediate layer is made of ZnO. The spin injection type spatial light modulator according to claim 4, wherein the same main component of each of the magnetization direction variable layer, the magnetization direction fixed layer, and the nonmagnetic intermediate layer is TiO ₂ or ZnO. The magnetization direction variable layer and the magnetization direction fixed layer are made of Co-added TiO ₂ ,
The spin injection spatial light modulator according to claim 8, wherein the nonmagnetic intermediate layer is made of Nb-added TiO ₂ . The magnetization direction variable layer and the magnetization direction fixed layer are made of Mn-added ZnO,
The spin injection spatial light modulator according to claim 8, wherein the nonmagnetic intermediate layer is made of ZnO. A lattice matching layer is formed under the magnetization direction variable layer,
The spin injection spatial light modulator according to claim 2, wherein the magnetization direction variable layer is epitaxially grown on the lattice matching layer. A lattice matching layer is formed under the magnetization direction variable layer,
The spin injection spatial light modulator according to claim 2, wherein the magnetization direction variable layer, the nonmagnetic intermediate layer, and the magnetization direction fixed layer are epitaxially grown.   A pair of electrode layers for applying a current is disposed on both sides in the stacking direction of the multilayer element body, and at least the electrode layers where light enters and exits are made of a transparent electrode material. 12. The spin injection type spatial light modulator according to any one of the above. The transparent electrode material includes indium zinc oxide (IZO), indium tin oxide (ITO), tin oxide (SnO ₂ ), antimony-tin oxide (ATO), zinc oxide (ZnO), The spin injection spatial light modulator according to claim 13, which is fluorine-doped tin oxide (FTO) or indium oxide (In ₂ O ₃ ).   The nonmagnetic layer that does not prevent spin conduction is inserted between the magnetization direction variable layer and the nonmagnetic intermediate layer and / or between the magnetization direction variable layer and the nonmagnetic intermediate layer. Item 15. The spin injection type spatial light modulator according to any one of Items 14.   An optical modulator comprising the spin injection spatial light modulators according to claim 1 arranged in a matrix.

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