JP2020160220A - Domain wall displacement type spatial optical modulation element and domain wall displacement type spatial light modulator - Google Patents

Abstract

To provide a domain wall displacement type spatial optical modulation element that can be improved in opening rate without being accompanied by increase of a drive current, and a domain wall displacement type spatial light modulator using the element.SOLUTION: A domain wall displacement type spatial optical modulation element comprises a plurality of optical modulation bodies such that a through hole electrode is employed as an electrode and a transparent electrode is arranged over an optical modulation part. Specifically, a first ferromagnetic exchange coupling part A has through hole electrodes 511, 514 arranged between first ferromagnetic layers 501, 502 and second ferromagnetic layers 504a, 504b, and a second ferromagnetic exchange coupling part B has through hole electrodes 512, 513 arranged between second ferromagnetic layers 504a, 504b and a transparent electrode layer 510.SELECTED DRAWING: Figure 5B

Description

The present invention is a magneto-optical spatial light modulator that displays the brightness and darkness of light by controlling the magnetic domain structure of the optical domain by moving the domain wall, which is promising as a spatial light modulator for three-dimensional holography with a wide field of view (hereinafter referred to as “spatial light modulator”). The present invention relates to a magnetic domain moving spatial light modulator constituting the “domain wall moving spatial light modulator”) and a magnetic domain moving spatial light modulator including the domain wall moving spatial light modulator.

Conventionally, in order to secure a viewing range of 30 degrees or more, which is practical in stereoscopic holography, it is necessary to set the pixel pitch of the spatial light modulator (SLM), which is a display device, to 1 micron or less. Existing SLMs such as liquid crystals and digital micromirror devices (DMDs) have a pixel pitch of about 5 microns, and further miniaturization is difficult.

On the other hand, a magneto-optical spatial optical modulator (MOSLM) that uses spin injection magnetization reversal and domain wall movement to rewrite pixels needs to improve performance from the viewpoint of light utilization efficiency and operating current, but it is about 1 micron. Pixel pitch can be realized (see Patent Document 1).

MOSLM is a device that realizes light modulation by assigning light and dark rotation of a plane of polarization of light according to the direction of magnetization. Here, the domain wall moving type SLM proposed by the applicant has a structure in which magnetization fixing layers are arranged at both ends of the optical modulation layer, so that the expansion / reduction of the magnetic domain can be controlled by the direction of the current flowing through the optical modulation layer. Yes (see Patent Document 2).

The domain wall moving type SLM can be expected to consume less power than the MOSLM using spin injection magnetization reversal. On the other hand, it is necessary to give a sufficient coercive force difference to the three types of ferromagnetic layers, the photomodulation layer and the magnetization fixing layers at both ends (first magnetization fixation layer and second magnetization fixation layer), and a complicated device structure. It is necessary to realize advanced device design within one pixel, which is premised on 1 micron or less, such as the need to precisely manufacture.

Here, in order to design a difference in the coercive force between the magnetization fixing layer 1 and the magnetization fixing layer 2, a material having a different coercive force or a ferromagnetic member having a layer structure is applied to both, or only one magnetization fixing layer is used. Alternatively, a method of irradiating an ion beam or the like can be considered. However, these forming processes require high-precision alignment for microfabrication in addition to complicated procedures.

On the other hand, in the domain wall moving type SLM proposed by the applicant, two magnetization-fixing layers having a specific structure are formed in one process and maintained between the magnetization-fixing layer 1 and the magnetization-fixing layer 2. Gives a magnetic force difference (see Patent Documents 3 and 4). With such a configuration, the manufacturing procedure can be simplified and the number of highly accurate alignments can be omitted, so that the domain wall movable type SLM, which has been difficult to manufacture, can be manufactured relatively easily. be able to.

Japanese Unexamined Patent Publication No. 2012-141402 Japanese Patent Application No. 2017-109478 Japanese Patent Application No. 2018-115881 Japanese Patent Application No. 2018-127489 JP-A-2017-167430 Japanese Unexamined Patent Publication No. 2005-191032

A. Yamaguchi, T.M. Ono, S.M. Nasu, K.K. Miyake, K.K. Mibu, and T. et al. Shinjo, "Real-Space Observation of Current-Driven Domain Wall Motion in Submicron Magnetic Wires", Physical Review Letters, United States of America, American Physical Society, 20 February 2004, Volume 92, Number 7, pp. 077205-1-077205-4 K. Aoshima, R.M. Ebisawa, N.M. Funabashi, K.K. Kuga, and K. Machida, "Current-induced domain-wall motion in patterned nanowires with various Gd-Fe compositions for magneto-optical light modulator applications", Japanese Journal of Applied Physics, Japan, The Japan Society of Applied Physics, 7 August 2018, Volume 57, pp. 09TC03-1-09TC03-4

In the domain wall moving type SLM, the effective optical modulation region is increased by improving the aperture ratio, so that a brighter stereoscopic image can be reproduced.

Here, one pixel of the domain wall moving space light modulator is a domain wall moving space light modulation element composed of a magnetization fixing layer and a light modulation layer, but the width of the light modulation layer is widened in order to improve the aperture ratio. Then, the drive current increases. On the other hand, there has been proposed a method of improving the aperture ratio while suppressing an increase in the drive current by arranging the optical modulation layer elongated in the pixel (see, for example, Patent Document 5).

However, it is known that the domain wall is trapped in the photomodulation layer having a shape other than the rectangle (Patent Document 6). Further, since the moving distance of the domain wall is proportional to the driving current density (Non-Patent Documents 1 and 2), the effect of reducing the current by arranging the optical modulation layer in an elongated manner is limited.

The present invention has been made in view of the above, and an object of the present invention is a domain wall moving space for constructing a domain wall moving spatial light modulator capable of improving the aperture ratio without increasing the driving current. An object of the present invention is to provide a light modulation element and a domain wall moving space light modulator including the domain wall moving space light modulation element.

The present inventors have conducted diligent studies to solve the above problems. Then, in the domain wall moving space light modulator constituting the domain wall moving space light modulator, if the electrode is a through-hole electrode and a plurality of light modulators in which transparent electrodes are arranged above the optical modulation unit are provided. , It has been found that the moving distance of the domain wall can be shortened, and as a result, an element having a small drive current density can be formed, and the present invention has been completed.

(1) That is, in the present invention, an optical modulation unit (for example, an optical modulation unit C described later) that changes the direction of polarization of incident light and emits the light, and a coerking force that is arranged at both ends of the optical modulation unit and is different from each other. It has a first ferromagnetic exchange coupling portion (for example, a first ferromagnetic exchange coupling portion A described later) and a second ferromagnetic exchange coupling portion (for example, a second ferromagnetic exchange coupling portion B described later). A magnetic wall moving space optical modulation element including a plurality of optical modulators, wherein both the first ferromagnetic exchange coupling portion and the second ferromagnetic exchange coupling portion are first ferromagnetic layers (for example,) made of a ferromagnetic material. , The first ferromagnetic layer 501, 502), which will be described later, and the second ferromagnetic layer (which is formed on the first ferromagnetic layer and is made of a ferromagnetic material to be ferromagnetically exchange-coupled with the first ferromagnetic layer. For example, the second ferromagnetic layers 504a and 504b described later) and through-hole electrodes (for example, through-hole electrodes 511, 512, 513, 514 described later) are provided, and the first strength of the second ferromagnetic layer is provided. A transparent electrode layer (for example, a transparent electrode layer 510 described later) is provided on the surface opposite to the magnetic layer, and the first ferromagnetic exchange coupling portion includes the first ferromagnetic layer and the second ferromagnetic layer. The through-hole electrode is arranged between the two, and in the second ferromagnetic exchange coupling portion, the through-hole electrode is arranged between the second ferromagnetic layer and the transparent electrode layer. It is a type space light modulation element.

(2) In the magnetic wall moving type spatial optical modulator of (1), the optical modulator is substantially rectangular, the long sides are arranged substantially parallel, and in the adjacent optical modulator, the first The ferromagnetic exchange coupling portion and the second ferromagnetic exchange coupling portion are alternately arranged, and in the adjacent optical modulator, the first ferromagnetic exchange coupling portion and the second ferromagnetic exchange coupling portion The first ferromagnetic layer may be shared.

(3) In another invention, the first ferromagnetic exchange has a coercive force different from that of an optical modulation unit (for example, an optical modulation unit C described later) that changes the direction of polarization of incident light and emits the light. Magnetic wall moving type including a photomodulator having a coupling portion (for example, a first ferromagnetic exchange coupling portion A described later) and a second ferromagnetic exchange coupling portion (for example, a second ferromagnetic exchange coupling portion B described later). In the space optical modulation element, the magnetic wall moving type space optical modulation element, two first ferromagnetic exchange coupling portions are arranged at both ends of the optical modulation portion, and one second ferromagnetic exchange coupling portion is provided. The portions are arranged between the two first ferromagnetic exchange coupling portions, or the two second ferromagnetic exchange coupling portions are arranged at both ends of the optical modulation portion and one said first. 1 Ferromagnetic exchange coupling portion is arranged between the two said second ferromagnetic exchange coupling portion, and both the first ferromagnetic exchange coupling portion and the second ferromagnetic exchange coupling portion are strong. A first ferromagnet made of a magnetic material (for example, first ferromagnets 601a, 601b, 602 described later) and the first ferromagnet formed on the first ferromagnet and made of a ferromagnetic material, so that the first ferromagnetism is formed. A second ferromagnetic layer (eg, second ferromagnetic layers 604a, 604b, 604c, 604d, described below) and a through-hole electrode (eg, through-hole electrodes 611, 612, 613, 614 described below) that are ferromagnetically exchange-coupled with the layer. , 615, 616, 617), and a transparent electrode layer (for example, transparent electrode layers 610a and 610b described later) is provided on the surface of the second ferromagnetic layer opposite to the first ferromagnetic layer. In the first ferromagnetic exchange coupling portion, the through-hole electrode is arranged between the first ferromagnetic layer and the second ferromagnetic layer, and in the second ferromagnetic exchange coupling portion, the second ferromagnetic exchange coupling portion. It is a magnetic wall moving type space light modulation element in which the through-hole electrode is arranged between the ferromagnetic layer and the transparent electrode layer.

(4) In the domain wall moving space light modulation element of (3), the domain wall moving space light modulation element includes a plurality of the light modulators, the optical modulation unit is substantially rectangular, and the long side is substantially rectangular. In the optical modulators arranged in parallel and in adjacent rows, the first ferromagnetic exchange coupling portion and the second ferromagnetic exchange coupling portion are alternately arranged, and the above-mentioned in the adjacent row. In the optical modulator, the first ferromagnetic exchange coupling portion and the first ferromagnetic layer of the second ferromagnetic exchange coupling portion may be shared.

(5) Another invention is a domain wall moving space light modulator including any of the plurality (1) to (4) domain wall moving space light modulators, wherein the plurality of domain wall moving space light is generated. This is a domain wall moving spatial light modulator in which the modulation elements are arranged in a grid pattern in a first direction and a second direction orthogonal to the first direction.

The domain wall movable spatial light modulator of the present invention can realize an improvement in the aperture ratio without increasing the drive current.

It is a perspective view of the domain wall moving type spatial light modulation element described in Patent Document 2. It is a figure which shows the operation of the domain wall moving type spatial light modulation element described in Patent Document 2. It is a top view of the domain wall moving type spatial light modulator described in Patent Document 2. It is a top view of the domain wall moving type spatial light modulator described in Patent Document 3. It is a top view of the domain wall moving type spatial light modulator described in Patent Document 3. It is a top view of the domain wall moving type spatial light modulator described in Patent Document 4. It is a top view of the domain wall moving type spatial light modulation element described in Patent Document 5. It is a top view of the domain wall moving type spatial light modulation element described in Patent Document 5. It is a top view of the domain wall moving type spatial light modulation element which concerns on one Embodiment of this invention. It is sectional drawing of the magnetic domain wall movable type spatial light modulation element which concerns on one Embodiment of this invention. It is sectional drawing of the magnetic domain wall movable type spatial light modulation element which concerns on one Embodiment of this invention. It is a top view of the domain wall moving type spatial light modulation element which concerns on one Embodiment of this invention. It is sectional drawing of the magnetic domain wall movable type spatial light modulation element which concerns on one Embodiment of this invention. It is sectional drawing of the magnetic domain wall movable type spatial light modulation element which concerns on one Embodiment of this invention.

The magnetic wall moving spatial light modulator 90 of the present invention includes the magnetic wall moving spatial light modulator 90 (shown in FIGS. 1A to 1C) described in Patent Document 2 and the magnetic wall moving spatial light modulator 100 described in Patent Document 3. And 200 (shown in FIGS. 2A to 2B), and the magnetic wall mobile spatial light modulator 400 (shown in FIG. 3) described in Patent Document 4, have a common configuration by the same mechanism.

Therefore, the domain wall moving spatial light modulator of the present invention will be described in detail with the description of the domain wall moving spatial light modulator and the domain wall moving optical modulator described in Patent Documents 2 to 4. For convenience of explanation, the top, bottom, left, and right in the drawing will be described as the top, bottom, left, and right of the domain wall movable spatial light modulation element.

<Magnetic characteristics>
The magnetic characteristics of the domain wall moving spatial light modulation element will be described with reference to the domain wall moving spatial light modulation element 91 described in Patent Document 2.

FIG. 1A is a perspective view of a domain wall moving space light modulation element constituting the domain wall moving space light modulator described in Patent Document 2. FIG. 1B is a diagram showing the operation of the domain wall moving space light modulation element constituting the domain wall moving space light modulator described in Patent Document 2. FIG. 1C is a top view of the domain wall movable spatial light modulator described in Patent Document 2. The arrows in FIGS. 1A and 1B indicate the directions in the magnetization direction.

The domain wall moving space light modulator 90 described in Patent Document 2 includes a plurality of domain wall moving space light modulation elements 91 utilizing the domain wall movement. Further, as shown in FIG. 1A, the magnetic domain wall moving type spatial light modulation element 91 includes a first ferromagnetic exchange coupling portion 1, a second ferromagnetic exchange coupling portion 2, and an optical modulation portion 3. It is formed on a substrate such as Si (not shown).

The first ferromagnetic exchange coupling portion 1 and the second ferromagnetic exchange coupling portion 2 are general metal electrode materials such as metals such as Cu, Al, Au, Ag, Ru, Ta, and Cr and alloys thereof (not shown), respectively. The lower electrode formed by is provided in the lowermost layer, and the pulse current can be applied by connecting the pulse current source 9 to the lower electrode.

As shown in FIG. 1B, in the first ferromagnetic exchange coupling portion 1 in the domain wall moving type spatial light modulation element 91 described in Patent Document 2, the first magnetization fixed layer 11 and the light modulation layer 30 are laminated. It is a composition. In the first ferromagnetic exchange coupling portion 1 shown in FIG. 1B, the non-magnetic metal layer 12 and the buffer layer 13 are arranged between the first magnetization fixing layer 11 and the optical modulation layer 30.

In the first ferromagnetic exchange coupling portion 1 of the domain wall moving type spatial light modulation element 91, the first magnetization fixed layer 11 and the light modulation layer 30 are ferromagnetically exchanged coupled via the non-magnetic metal layer 12 and the buffer layer 13. Has been done. Due to this ferromagnetic exchange coupling, the magnetization direction of the first magnetization fixed layer 11 and the magnetization direction of the optical modulation layer 30 in the first ferromagnetic exchange coupling portion 1 are reversed at the same time.

Further, the second ferromagnetic exchange coupling portion 2 in the domain wall moving type spatial light modulation element 91 has a configuration in which the second magnetization fixing layer 21 and the light modulation layer 30 are laminated. In the second ferromagnetic exchange coupling portion 2 shown in FIG. 1B, the non-magnetic metal layer 22 and the buffer layer 23 are arranged between the second magnetization fixing layer 21 and the optical modulation layer 30.

In the second ferromagnetic exchange coupling portion 2 of the domain wall moving space optical modulation element 91, the second magnetization fixing layer 21 and the optical modulation layer 30 are formed of the non-magnetic metal layer 22 as in the first ferromagnetic exchange coupling portion 1. And is ferromagnetically exchange-coupled via the buffer layer 23. Due to this ferromagnetic exchange coupling, the magnetization direction of the second magnetization fixed layer 21 and the magnetization direction of the optical modulation layer 30 in the second ferromagnetic exchange coupling portion 2 are reversed at the same time.

Then, as shown in FIGS. 1A and 1B, the domain wall moving type spatial light modulation element 91 is designed so that the magnetization direction of the first ferromagnetic exchange coupling portion 1 is upward, while the second ferromagnetic exchange coupling is performed. The magnetization direction of the part 2 is designed to face downward.

A magnetic domain 33 extending on a plane orthogonal to the direction connecting the two ferromagnetic exchange coupling portions is formed in the optical domain wall 3 of the domain wall moving space optical modulation element 91, and magnetic domains formed on both sides of the magnetic wall 33. The magnetization directions of 31 and 32 are opposite to each other. In the domain wall moving type spatial optical modulation element 91, as shown in FIGS. 1A and 1B, the magnetization direction of the magnetic domain 32 on the first ferromagnetic exchange coupling portion 1 side of the domain wall 33 is downward, and the magnetization direction is downward from the domain wall 33. The magnetization direction of the magnetic domain 31 on the second ferromagnetic exchange coupling portion 2 side is upward.

By forming the magnetic domains 31 and 32 having different directions of magnetization through the domain wall 33 in the optical modulation unit 3, the domain wall moving type spatial light modulation element 91 can function as a spatial light modulation element. it can.

For example, when the magnetic wall moving type spatial light modulation element 91 is used as a reflection type spatial light modulation element, light having uniform polarization is emitted from above the magnetic wall moving space light modulation element 91 onto the upper surface of the light modulation unit 3. On the other hand, when incident light occurs, the rotation angle of the plane of polarization of the reflected light differs depending on the direction of the magnetization direction. Therefore, the light can be modulated by assigning each reflected light according to the rotation angle of these different polarizing surfaces to the light and darkness of the light through the polarizing filter. Further, by forming the substrate with a translucent material such as glass or sapphire, the domain wall moving type spatial light modulation element 91 can function as a transmission type spatial light modulation element.

(Domain wall formation mechanism)
Here, the domain wall generation mechanism in the domain wall moving space light modulation element of the present invention will be described with reference to FIGS. 1A and 1B regarding the domain wall moving space light modulation element 91 described in Patent Document 2.

First, in order to form the domain wall 33 in the optical modulation unit 3, the coercive force of the first magnetization fixed layer 11 that ferromagnetically exchanges and couples with the optical modulation layer 30 and the second magnetization that ferromagnetically exchanges and couples with the optical modulation layer 30 It is necessary to make the coercive force of the fixed layer 21 different from each other.

Here, when the coercive force of the first magnetization fixed layer 11 is designed to be smaller than the coercive force of the second magnetization fixed layer 21, the coercive force of the first ferromagnetic exchange coupling portion 1 is set to Hc1 and the second strong force. Assuming that the coercive force of the magnetic exchange coupling portion 2 is Hc2 and the coercive force of the photomodulation layer is Hc_m, the relationship of Hc2> Hc1> Hc_m is established.

Then, when a magnetic field having a strength H of H> Hc2 is applied downward to the element having a structure in which the above-mentioned coercive force relationship is established, the first ferromagnetic exchange coupling portion 1, the first. 2 In both the ferromagnetic exchange coupling unit 2 and the optical modulation unit 3, the direction of the magnetization direction is downward.

On the other hand, when a magnetic field having a strength H'of Hc2> H'> Hc1 is applied upward to the element, the direction of the magnetization direction of the second ferromagnetic exchange coupling portion 2 remains downward. On the other hand, the directions of the magnetization directions of the first ferromagnetic exchange coupling unit 1 and the optical modulation unit 3 both change upward.

At this time, initial magnetic domains 31a and 32a are generated at both ends of the optical modulation unit 3, as shown in FIG. 1B. More specifically, at the end of the optical modulation unit 3 on the first ferromagnetic exchange coupling portion 1 side, the first ferromagnetism is caused by the leakage magnetic field from the first ferromagnetic exchange coupling portion 1 (broken line arrow in FIG. 1B). An initial magnetic domain 32a in the downward magnetization direction, which is antiparallel to the upward magnetization of the exchange coupling portion 1, is generated. Further, at the end of the optical modulation unit 3 on the second ferromagnetic exchange coupling portion 2 side, a second ferromagnetic exchange coupling is formed by a magnetic domain leaking from the second ferromagnetic exchange coupling portion 2 (broken line arrow in FIG. 1B). An initial magnetic domain 31a in the upward magnetization direction, which is antiparallel to the downward magnetization of part 2, is generated.

Next, in this state, a pulse current is applied from the pulse current source 9, and the first ferromagnetic exchange coupling portion 1 to the second ferromagnetic exchange coupling portion 2 or the second ferromagnetic exchange coupling portion 2 to the first ferromagnetic exchange coupling portion 2 A pulse current is passed toward the part 1. Then, the domain wall 33 formed by the generation of the initial magnetic domains 31a and 32a can be moved in the direction opposite to the direction of the pulse current (the same direction as the flow of electrons). As a result, as shown in FIG. 1B, the direction of magnetization of the optical modulation region 300 excluding both ends of the optical modulation section 3 is reversed (in the example of FIG. 1B, the direction of magnetization of the optical modulation region 300 is inverted upward). It becomes possible.

<First Embodiment>
[Structure of domain wall moving spatial light modulation element]
FIG. 5A is a top view of the domain wall moving space light modulation element 500 according to the first embodiment of the present invention, and FIG. 5B is a cross-sectional view taken along the line DD'of the domain wall moving space light modulation element 500. 5C is a cross-sectional view taken along the line E-E'of the domain wall moving type spatial light modulation element 500.

The domain wall moving spatial light modulator 500 of the present invention according to the first embodiment has two light modulators, each of which is of incident light, as shown in FIGS. 5B and 5C. The light modulation section C that emits light by changing the direction of polarized light, and the first ferromagnetic exchange coupling section A and the second ferromagnetic exchange coupling section B that are arranged at both ends of the light modulation section C and have different coercive forces. Have.

The first ferromagnetic exchange coupling portion A is formed on the first ferromagnetic layers 501 and 502 made of a ferromagnetic material and the first ferromagnetic layers 501 and 502, and is made of a ferromagnetic material to form the first ferromagnetism. It includes second ferromagnetic layers 504a and 504b that are ferromagnetically exchange-coupled to layers 501 and 502, and through-hole electrodes 511 and 514. Further, a transparent electrode layer 510 is provided on the surface of the second ferromagnetic layers 504a and 504b opposite to the first ferromagnetic layers 501 and 502.

The second ferromagnetic exchange coupling portion B is formed on the first ferromagnetic layers 501 and 502 made of a ferromagnetic material and the first ferromagnetic layers 501 and 502, and is made of a ferromagnetic material to form the first ferromagnetism. It includes second ferromagnetic layers 504a and 504b that are ferromagnetically exchange-coupled with layers 501 and 502, and through-hole electrodes 512 and 513. Further, a transparent electrode layer 510 is provided on the surface of the second ferromagnetic layers 504a and 504b opposite to the first ferromagnetic layers 501 and 502.

Then, in the domain wall moving type spatial light modulation element 500, the parts other than the first ferromagnetic layers 501 and 502, the second ferromagnetic layers 504a and 504b, the through-hole electrodes 511, 512, 513, 514, and the transparent electrode layer 510 are , Is made of insulating material 506.

In the first ferromagnetic exchange coupling portion A in the optical modulator constituting the domain wall moving space optical modulation element 500 according to the first embodiment, the first ferromagnetic layers 501 and 502 and the second ferromagnetic layers 504a and 504b Through-hole electrodes 511 and 514 are arranged between them, and in the second ferromagnetic exchange coupling portion B, through-hole electrodes 512 and 513 are arranged between the second ferromagnetic layers 504a and 504b and the transparent electrode layer 510. ing.

Further, a pulse current can be applied to the first ferromagnetic layers 501 and 502 by connecting the pulse current source 509.

[First ferromagnetic exchange coupling part]
In the optical modulator constituting the magnetic wall moving space optical modulator of the present invention, the first ferromagnetic exchange coupling portion is formed on the first ferromagnetic layer made of a ferromagnetic material and the first ferromagnetic layer, and is strong. A second ferromagnetic layer which is made of a magnetic material and has a ferromagnetic exchange coupling with the first ferromagnetic layer and a through-hole electrode are provided, and the through-hole electrode is composed of a first ferromagnetic layer and a second ferromagnetic layer. Placed in between.

Then, in the optical modulator constituting the magnetic domain wall moving space optical modulation element 500 according to the first embodiment, the first ferromagnetic exchange coupling portion in the DD'cross-sectional view shown in FIG. 5B and FIG. 5C are shown. In the first ferromagnetic exchange coupling portion in the EE'cross-sectional view, through-hole electrodes 511 and 514 are arranged between the first ferromagnetic layers 501 and 502 and the second ferromagnetic layers 504a and 504b.

In the magnetic domain wall moving type spatial light modulation element 500 of the present invention shown in FIGS. 5A to 5C, the first ferromagnetic exchange coupling portion A in each light modulator is located at the end of the light modulation portion C and is second ferromagnetic. It is arranged in pairs with the exchange coupling portion B. Further, in the light modulator constituting the domain wall moving type spatial light modulation element 500, the upper surfaces of the light modulation unit C, the first ferromagnetic exchange coupling portion A and the second ferromagnetic exchange coupling portion B are continuously flush with each other. Is formed as.

(First ferromagnetic layer)
The first ferromagnetic layer is made of a ferromagnetic material. The first ferromagnetic layer is a layer in which the magnetization direction is fixed in one direction and has a large coercive force. The first ferromagnetic layer shall have magnetic anisotropy in the same direction as the second ferromagnetic layer, and when a ferromagnetic material having perpendicular magnetic anisotropy is used for the second ferromagnetic layer, the first ferromagnetic layer It is preferable to use a ferromagnetic material having vertical magnetic anisotropy as the ferromagnetic layer. In the present invention, it is preferable that both the first ferromagnetic layer and the second ferromagnetic layer are made of a ferromagnetic material having vertical magnetic anisotropy.

The material constituting the first ferromagnetic layer is not particularly limited. For example, the non-magnetic layer is sandwiched between a magnetized fixed layer in which the magnetization is fixed in the vertical direction and a magnetization free layer in which the magnetization direction can be reversed. It is composed of a CPP-GMR (Current Perpendicular to the Plane Giant Magnetoresistance) element having a vertical magnetic anisotropy of the structure to be magnetized, and a ferromagnetic material known as a magnetization fixing layer such as a TMR element. Is possible.

Specific examples thereof include transition metals such as Fe, Co and Ni and alloys containing them, for example, TbFe-based, TbFeCo-based, CoCr-based, CoPt-based, CoPd-based and FePt-based alloys. By forming with these materials, the coercive force of the first ferromagnetic layer can be increased, and the magnetization direction of the first ferromagnetic layer can be fixed so as not to be easily changed by an external magnetic field. ..

Further, the first ferromagnetic layer may be a multi-layered laminate in which layers of these transition metals and layers of non-magnetic metals are alternately laminated. Examples of such a configuration include multilayer films such as Co / Pt, Fe / Pt, and Co / Pd. By forming a laminate using these ferromagnetic materials, a first ferromagnetic layer having a strong perpendicular magnetic anisotropy and a large coercive force can be obtained.

Here, the above-mentioned multilayer film has a property that the coercive force is increased by heat treatment. Therefore, when the first ferromagnetic layer made of the multilayer film is heat-treated, the coercive force of the ferromagnetic exchange coupling portion A after coupling with the second ferromagnetic layer also increases, so that the coercive force with the photomodulator C is maintained. The magnetic force difference can be made larger.

In the light modulator constituting the magnetic domain wall moving type spatial light modulation element 500 according to the first embodiment of the present invention shown in FIG. 5B, the first ferromagnetic layer 501 in the first ferromagnetic exchange coupling portion A is the second strong. It is formed under the magnetic layer 504a. Further, in the optical modulator shown in FIG. 5C, the first ferromagnetic layer 502 in the first ferromagnetic exchange coupling portion A is formed under the second ferromagnetic layer 504b.

Further, as shown in FIGS. 5A to 5C, in the magnetic domain wall moving space optical modulation element 500 according to the first embodiment of the present invention, the first ferromagnetic exchange coupling portion arranged at both ends of the optical modulation portion C. A pulse current source 509 is connected to the first ferromagnetic layers 501 and 502 of A and the second ferromagnetic exchange coupling portion B, and a pulse current can be applied.

(Second ferromagnetic layer)
The second ferromagnetic layer is formed on the first ferromagnetic layer and is made of a ferromagnetic material. As described above, the second ferromagnetic layer shall have magnetic anisotropy in the same direction as the first ferromagnetic layer, and when a ferromagnetic material having vertical magnetic anisotropy is used for the first ferromagnetic layer. It is preferable to use a ferromagnetic material having vertical magnetic anisotropy for the second ferromagnetic layer as well. In the present invention, it is preferable that both the first ferromagnetic layer and the second ferromagnetic layer are made of a ferromagnetic material having vertical magnetic anisotropy.

A known ferromagnetic material can be applied to the second ferromagnetic layer, and it is preferable to apply a material having a large magneto-optical effect (Kerr effect). In order to increase the magnetic optical effect, it is preferable to use a magnetic layer having vertical magnetic anisotropy. For example, a multilayer film such as a Co / Pd multilayer film in which a transition metal and Pd, Pt, and Cu are repeatedly laminated. Alternatively, an alloy (RE-TM alloy) of a rare earth metal such as TbFeCo or GdFe and a transition metal can be mentioned. Among them, a GdFe layer made of GdFe can be preferably used.

In the light modulator constituting the magnetic domain wall moving type spatial light modulation element 500 according to the first embodiment of the present invention shown in FIG. 5B, the second ferromagnetic layer 504a in the first ferromagnetic exchange coupling portion A is the first strong. It is formed on the magnetic layer 501. Further, in the optical modulator shown in FIG. 5C, the second ferromagnetic layer 504b in the first ferromagnetic exchange coupling portion A is formed on the first ferromagnetic layer 502.

(Through hole electrode)
The light modulator constituting the magnetic wall moving type spatial light modulation element of the present invention includes through-hole electrodes in the first ferromagnetic exchange coupling portion and the second ferromagnetic exchange coupling portion. The domain wall moving type spatial light modulation element of the present invention is characterized in that a through-hole electrode is provided inside the element. Thereby, for example, when a plurality of optical modulators are provided and the optical modulation layers are arranged in parallel, the direction of the current flowing through the optical modulation layers can be the same. Therefore, the device can be designed with the current path in the optical modulation layer as a straight line and the shortest distance, and a device with a low current and a high aperture ratio can be realized.

The size of the through hole in the through hole electrode is not particularly limited as long as the drive current in the domain wall moving type spatial light modulation element can be connected. Further, the manufacturing method thereof is not particularly limited.

The metal to be filled in the through hole in the through-hole electrode is not particularly limited, and is a conductive and stable metal, and a known material can be used as the electrode. For example, ruthenium, tantalum, tungsten, gold, silver, copper, aluminum, oxides containing indium, tin, zinc, gallium and the like known as general transparent electrode materials can be mentioned.

In the light modulator constituting the magnetic domain wall moving type spatial light modulation element 500 according to the first embodiment of the present invention shown in FIGS. 5A to 5C, the first ferromagnetic exchange coupling portion A has through-hole electrodes 511 and 514. To be equipped.

In the first ferromagnetic exchange coupling portion A of the light modulator constituting the magnetic wall moving type spatial light modulation element 500 shown in FIG. 5B, the through-hole electrode 511 has the first ferromagnetic layer 501 and the second ferromagnetic layer 504a. It is placed between and. Further, in the optical modulator shown in FIG. 5C, the through-hole electrode 514 in the first ferromagnetic exchange coupling portion A is arranged between the first ferromagnetic layer 502 and the second ferromagnetic layer 504b.

In the domain wall moving space light modulation element 500 according to the first embodiment, the through-hole electrodes 511, 512, 513, 514 are formed in a layer made of an insulating member 506, and the domain wall moving space light modulation element 500 It is stacked and arranged at a predetermined position.

The insulating member 506 forming the layer on which the through-hole electrodes 511, 512, 513, 514 are formed is not particularly limited as long as it is made of an insulating material. For example, SiO ₂ , SiN, MgO and the like can be mentioned. Further, the manufacturing method thereof is not particularly limited, and the through-hole electrode can be manufactured by a known method.

[Second ferromagnetic exchange coupling part]
In the optical modulator constituting the domain wall moving space optical modulator of the present invention, the second ferromagnetic exchange coupling portion is formed on the first ferromagnetic layer made of a ferromagnetic material and the first ferromagnetic layer, and is strong. A second ferromagnetic layer, which is made of a magnetic material and is ferromagnetically exchange-coupled with the first ferromagnetic layer, and a through-hole electrode are provided, and the through-hole electrode is located between the second ferromagnetic layer and the transparent electrode layer. Be placed.

Then, in the optical modulator constituting the domain wall movable space optical modulation element 500 according to the first embodiment, the second ferromagnetic exchange coupling portion in the DD'cross-sectional view shown in FIG. 5B and FIG. 5C are shown. In the second ferromagnetic exchange coupling portion in the EE'cross-sectional view, through-hole electrodes 512 and 513 are arranged between the second ferromagnetic layers 504a and 504b and the transparent electrode layer 510.

In the magnetic domain wall moving type spatial light modulation element 500 of the present invention shown in FIGS. 5A to 5C, the second ferromagnetic exchange coupling portion B in each light modulator is located at the end of the light modulation portion C and is first ferromagnetic. It is arranged in pairs with the exchange coupling portion A. Further, in the light modulator constituting the domain wall moving type spatial light modulation element 500, the upper surfaces of the light modulation unit C, the first ferromagnetic exchange coupling portion A and the second ferromagnetic exchange coupling portion B are continuously flush with each other. Is formed as.

(First ferromagnetic layer)
The first ferromagnetic layer in the second ferromagnetic exchange coupling portion is made of a ferromagnetic material. The material constituting the first ferromagnetic layer in the second ferromagnetic exchange coupling portion can be selected and used from the materials that can be used as the first ferromagnetic layer in the first ferromagnetic exchange coupling portion described above. ..

In the magnetic wall moving type spatial light modulation element of the present invention, the first ferromagnetic exchange coupling portion and the second ferromagnetic exchange coupling portion have coercive forces with each other in order to form the magnetic wall and the light modulation portion described later. Must be designed differently. Due to the difference in coercive force between the first ferromagnetic exchange coupling part and the second ferromagnetic exchange coupling part, it is possible to realize the initial magnetization direction antiparallel to each other at both ends of the optical modulation part, which is essential for optical modulation control, by an external magnetic field. It will be possible.

As a method of making the coercive force of the first ferromagnetic exchange coupling portion and the second ferromagnetic exchange coupling portion different, for example, the first ferromagnetic layer of the first ferromagnetic exchange coupling portion and the second ferromagnetic exchange coupling portion A method in which the first ferromagnetic layer and the first ferromagnetic layer have different shapes (for example, when the width of the first ferromagnetic layer of the first ferromagnetic exchange coupling portion is widened, the coercive force of the first ferromagnetic exchange coupling portion becomes small). , A method of heat-treating only one of them, a method of different layer structures from each other, and the like.

In the light modulator constituting the magnetic domain wall moving type spatial light modulation element 500 according to the first embodiment of the present invention shown in FIG. 5B, the first ferromagnetic layer 502 in the second ferromagnetic exchange coupling portion B is the second strong. It is formed under the magnetic layer 504a. Further, in the optical modulator shown in FIG. 5C, the first ferromagnetic layer 501 in the second ferromagnetic exchange coupling portion B is formed under the second ferromagnetic layer 504b.

(Second ferromagnetic layer)
The second ferromagnetic layer in the second ferromagnetic exchange coupling portion is formed on the first ferromagnetic layer and is made of a ferromagnetic material. Similar to the first ferromagnetic exchange coupling portion, the second ferromagnetic layer is assumed to have magnetic anisotropy in the same direction as the first ferromagnetic layer, and the first ferromagnetic layer has strong perpendicular magnetic anisotropy. When a magnetic material is used, it is preferable to use a ferromagnetic material having vertical magnetic anisotropy for the second ferromagnetic layer as well. In the present invention, it is preferable that both the first ferromagnetic layer and the second ferromagnetic layer are made of a ferromagnetic material having vertical magnetic anisotropy.

The material constituting the second ferromagnetic layer in the second ferromagnetic exchange coupling portion can be selected and used from the materials that can be used as the second ferromagnetic layer in the first ferromagnetic exchange coupling portion described above. ..

In the light modulator constituting the magnetic domain wall moving type spatial light modulation element 500 according to the first embodiment of the present invention shown in FIG. 5B, the second ferromagnetic layer 504a in the second ferromagnetic exchange coupling portion B is the first strong. It is formed on the magnetic layer 502. Further, in the optical modulator shown in FIG. 5C, the second ferromagnetic layer 504b in the second ferromagnetic exchange coupling portion B is formed on the first ferromagnetic layer 501.

(Through hole electrode)
As described above, the light modulator constituting the magnetic wall moving type spatial light modulation element of the present invention includes through-hole electrodes in the first ferromagnetic exchange coupling portion and the second ferromagnetic exchange coupling portion. The configuration of the through-hole electrode in the second ferromagnetic exchange coupling portion is the same as the configuration of the through-hole electrode in the first ferromagnetic exchange coupling portion.

In the magnetic domain wall moving type spatial light modulation element 500 according to the first embodiment of the present invention shown in FIGS. 5A to 5C, the second ferromagnetic exchange coupling portion B includes through-hole electrodes 512 and 513.

In the second ferromagnetic exchange coupling portion B of the light modulator constituting the magnetic wall moving type spatial light modulation element 500 shown in FIG. 5B, the through-hole electrode 512 is formed by the second ferromagnetic layer 504a and the transparent electrode layer 510. It is placed in between. Further, in the optical modulator shown in FIG. 5C, the through-hole electrode 513 in the second ferromagnetic exchange coupling portion B is arranged between the second ferromagnetic layer 504b and the transparent electrode layer 510.

[Optical modulator]
In the light modulator constituting the magnetic wall moving type spatial light modulation element of the present invention, the light modulation unit is a portion that changes the direction of polarization of the incident light and emits the light. At both ends of the optical modulation section, the first ferromagnetic exchange coupling section and the second ferromagnetic exchange coupling section described above have coercive forces different from each other.

In each of the light modulators constituting the domain wall moving type spatial light modulation element 500 according to the first embodiment shown in FIGS. 5A to 5C, the light modulation unit C is formed in a flat plate shape (rectangular shape) extending in a predetermined direction. A first ferromagnetic exchange coupling portion A and a second ferromagnetic exchange coupling portion B are arranged at both ends thereof. The optical modulation section C and the upper surfaces of the first ferromagnetic exchange coupling section A and the second ferromagnetic exchange coupling section B are continuously formed to be flush with each other.

That is, in each of the optical modulators constituting the domain wall moving space optical modulator 500 according to the first embodiment, the optical modulator C is a continuous layer of the second ferromagnetic layer 504a and a continuous layer of 504b. Each optical modulator is configured as the same layer as the second ferromagnetic layer in the first ferromagnetic exchange coupling portion A and the second ferromagnetic layer in the second ferromagnetic exchange coupling portion B.

A magnetic domain wall and a magnetic domain are formed in the optical modulation section of the domain wall moving type spatial light modulation element. This will be described later.

In the light modulator constituting the magnetic wall moving spatial light modulation element of the present invention, the shape of the optical modulation unit is not particularly limited, but it is similar to the optical modulator constituting the magnetic wall moving spatial light modulation element 500 of the first embodiment. In addition, it is preferable to form a flat plate (rectangular) extending in a predetermined direction.

Here, FIGS. 4A and 4B show top views of the domain wall movable spatial light modulation element described in Patent Document 5, which is a prior art. The light modulation portions (light modulation layers) 54 and 64 in the domain wall movable spatial light modulation elements 50 and 60 shown in FIGS. 4A and 4B are formed in an elongated shape having a bent portion.

The purpose of Patent Document 5 is to improve the aperture ratio while suppressing an increase in the drive current by arranging the optical modulation layers 54 and 64 in an elongated manner. However, the domain walls 53 and 63 formed in the domain wall moving spatial light modulation elements 50 and 60 described in Patent Document 5 move through the bent portion along the shapes of the light modulation layers 54 and 64. It becomes. Further, since the lengths of the optical modulation layers 54 and 64 are long, the moving distance of the domain walls 53 and 63 is also long.

Here, it is known that the moving distance of the domain wall is proportional to the drive current density (Non-Patent Documents 1 and 2), and when the optical modulation layer has a shape other than a rectangle, the domain wall captures the layer. It is also known to be (trapped) (Patent Document 6). Therefore, there is a limit to the effect of reducing the current due to the deformation of the optical modulation layer described in Patent Document 5.

On the other hand, in the light modulator constituting the magnetic wall moving type spatial light modulation element of the present invention, the shape of the light modulation unit can be rectangular. By making it rectangular, the domain wall can be linearly moved by the shortest distance, and the domain wall can be shortened, and as a result, an increase in the drive current can be suppressed.

Further, the magnetic wall moving type spatial light modulation element 500 according to the first embodiment has two light modulators, and two substantially rectangular light modulation units C are arranged in two rows with long sides of the rectangle. They are arranged so as to be substantially parallel. At the ends of the optical modulators adjacent to each other between the rows, the first ferromagnetic exchange coupling portion and the second ferromagnetic exchange coupling portion are alternately arranged, and the first ferromagnetism in the adjacent optical modulators. The exchange coupling portion and the first ferromagnetic layer of the second ferromagnetic exchange coupling portion are shared.

As described above, the magnetic wall moving type spatial light modulation element of the present invention can linearly move the magnetic wall and shorten the moving distance by making the shape of the light modulation portion of the constituent optical modulator rectangular. .. Then, as in the magnetic wall moving type spatial light modulation element 500 according to the first embodiment, a plurality of light modulators are arranged in one element, and each light modulator is provided with a rectangular light modulation unit. By arranging the light modulators in series, it is possible to realize a magnetic wall moving type spatial light modulation element capable of improving the aperture ratio without increasing the drive current.

[Transparent electrode layer]
In the magnetic wall moving type spatial light modulation element of the present invention, a transparent electrode layer is provided on the surface of the first ferromagnetic exchange coupling portion and the second ferromagnetic exchange coupling portion opposite to the first ferromagnetic layer of the second ferromagnetic layer. Be prepared.

The magnetic domain wall moving type spatial light modulation element of the present invention is provided with a through-hole electrode and a transparent electrode layer at the same time, so that a driving current flows inside the transparent electrode layer. That is, the flow of the driving current is bent only inside the transparent electrode layer, and the movement of the domain wall is not bent. Therefore, the domain wall formed by each optical modulator moves linearly in the optical modulator at a short distance. As a result, even if the aperture ratio of the element is improved, the drive current is not increased.

(Drive current)
In the magnetic domain wall moving type spatial light modulation element 500 according to the first embodiment shown in FIGS. 5A to 5C, the transparent electrode layer 510 is placed on the second ferromagnetic layers 504a and 504b, and the first ferromagnetic layer 501, It is arranged on the opposite side of the 502.

In FIGS. 5A to 5C, the drive current 505 in the magnetic domain wall moving type spatial light modulation element 500 according to the first embodiment is the first ferromagnetic exchange in the light modulator shown as a DD'cross section in FIG. 5B. It enters the second ferromagnetic layer 504a from the first ferromagnetic layer 501 of the coupling portion A and moves in the light modulation layer C from left to right. After that, when it reaches the second ferromagnetic exchange coupling portion B, it enters the transparent electrode layer 510 through the through-hole electrode 512, and moves by turning back from right to left inside the transparent electrode layer 510.

Subsequently, in the photomodulator shown as an EE'cross-sectional view in FIG. 5C, the second ferromagnetism of the second ferromagnetism exchange coupling portion B from the transparent electrode layer 510 through the through-hole electrode 513 at the end. After entering the layer 504b, moving through the optical modulation layer C from left to right and reaching the first ferromagnetic exchange coupling portion A at the end of the optical modulation layer C, the first ferromagnetic exchange coupling portion A 1 Outflow from the ferromagnetic layer 502.

The material constituting the transparent electrode layer is not particularly limited, and a known material can be used as the transparent electrode. For example, oxides containing indium, tin, zinc, gallium and the like can be mentioned.

The thickness of the transparent electrode layer is also not particularly limited, but is preferably in the range of 0.01 to 1 μm, for example. Within this range, microfabrication of the transparent electrode required for realizing the present invention becomes easy. Further, since the resistance value of the transparent electrode is equal to or less than that of the optical modulation layer, the current value required for desired driving can be obtained depending on the voltage value that can be applied by a transistor or the like.

[Other configurations]
The magnetic domain wall moving type spatial light modulation element of the present invention has an arbitrary layer, if necessary, in addition to the first ferromagnetic layer, the second ferromagnetic layer, the transparent electrode layer, and the layer on which the through-hole electrode is formed. You may.

[Magnetic characteristics]
The magnetic characteristics of the domain wall movable spatial light modulation element 500 according to the first embodiment will be described below.

Looking at the first ferromagnetic exchange coupling portion A of each optical modulator in the domain wall moving space optical modulation element 500, in the optical modulator shown in FIG. 5B, the second strength in the first ferromagnetic exchange coupling portion A The magnetic layer 504a is formed on the first ferromagnetic layer 501, and in the photomodulator shown in FIG. 5C, the second ferromagnetic layer 504b in the first ferromagnetic exchange coupling portion A is the first strong. It is formed on the magnetic layer 502. The second ferromagnetic layer 504a and the layer 504b are ferromagnetically exchange-coupled with the first ferromagnetic layers 501 and 502.

Similarly, looking at the second ferromagnetic exchange coupling portion B of each optical modulator in the domain wall moving space optical modulation element 500, in the optical modulator shown in FIG. 5B, the second ferromagnetic exchange coupling portion B The second ferromagnetic layer 504a in the above is formed on the first ferromagnetic layer 502, and in the photomodulator shown in FIG. 5C, the second ferromagnetic layer 504b in the second ferromagnetic exchange coupling portion B is , Is formed on the first ferromagnetic layer 501. The second ferromagnetic layer 504a and the layer 504b are ferromagnetically exchange-coupled with the first ferromagnetic layers 501 and 502.

Then, the magnetic walls 503a and 503b are formed in the optical modulation section C of each light modulator in the magnetic wall moving type spatial light modulation element 500 by utilizing the ferromagnetic exchange coupling formed based on the above-mentioned domain wall generation mechanism. Then, it functions as a domain wall moving type spatial light modulation element.

Specifically, in the magnetic wall moving type spatial light modulation element 500, in the light modulation section of the light modulator shown as a DD'cross-sectional view in FIG. 5B, the magnetization direction of the first ferromagnetic exchange coupling section A is upward. On the other hand, the magnetization direction of the second ferromagnetic exchange coupling portion B is designed to be downward.

Further, in the magnetic wall moving type spatial light modulation element 500, in the light modulation section of the light modulator shown as an EE'cross-sectional view in FIG. 5C, the magnetization direction of the first ferromagnetic exchange coupling section A is designed to be downward. On the other hand, the magnetization direction of the second ferromagnetic exchange coupling portion B is designed to be upward.

The domain wall 503a and 503b extending on a plane orthogonal to the direction connecting the two ferromagnetic exchange coupling portions are formed in the domain wall C in each optical modulator of the domain wall moving space optical modulator 500, and the domain wall is formed. The magnetization directions of the magnetic domains formed on both sides of 503a and 503b are opposite to each other. By forming the optical modulation unit C having such domain walls 503a and 503b, it can function as a domain wall moving type spatial light modulation element.

That is, in the domain wall moving type space optical modulation element 500, in the optical domain of the optical modulator shown as a DD'cross-sectional view in FIG. 5B, the magnetic domain on the first ferromagnetic exchange coupling portion A side of the domain wall 503a. The magnetization direction D51 is downward, and the magnetization direction D52 of the magnetic domain on the second ferromagnetic exchange coupling portion B side with respect to the domain wall 503a is upward.

Further, in the domain wall moving type space optical modulation element 500, in the optical domain of the optical modulator shown as an EE'cross-sectional view in FIG. 5C, the magnetic domain on the first ferromagnetic exchange coupling portion A side of the domain wall 503b. The magnetization direction D54 is upward, and the magnetization direction D53 of the magnetic domain on the second ferromagnetic exchange coupling portion B side with respect to the domain wall 503b is downward.

[Manufacturing method of domain wall moving spatial light modulation element]
The method for manufacturing the domain wall moving type spatial light modulation element according to the first embodiment is not particularly limited. For example, after forming a layer including a first ferromagnetic layer on a substrate, an insulating layer having a through-hole electrode is laminated, then a layer including a second ferromagnetic layer is laminated, and further, a through-hole electrode is formed. A method of laminating the insulating layers to be provided and finally laminating and forming a transparent electrode layer can be mentioned.

<Second Embodiment>
[Structure of domain wall moving spatial light modulation element]
FIG. 6A is a top view of the domain wall moving space light modulation element 600 according to the second embodiment of the present invention, and FIG. 6B is a sectional view taken along line FF'of the domain wall moving space light modulation element 600. 6C is a cross-sectional view taken along the line GG'of the domain wall moving type spatial light modulation element 600.

The domain wall moving space light modulation element of the present invention according to the second embodiment is a two-pixel element composed of a domain wall moving space light modulation element 600a and a domain wall moving space light modulation element 600b. The domain wall moving type spatial light modulation element 600a and the domain wall moving space light modulation element 600b each having one pixel are provided with two light modulators. That is, the magnetic domain wall moving type spatial light modulation element (600a + 600b) of the present invention according to the second embodiment is provided with a total of four light modulators.

As shown in FIGS. 6B and 6C, the light modulator constituting the magnetic domain wall movable spatial light modulation element (600a + 600b) according to the second embodiment emits light by changing the direction of polarization of the incident light. It has a light modulation section C to be used, and a first ferromagnetic exchange coupling section A and a second ferromagnetic exchange coupling section B arranged at both ends of the light modulation section C and having different coercive forces. In addition, in FIG. 6B and FIG. 6C, one of the optical modulators constituting the magnetic wall moving type spatial light modulation element 600a and the optical modulators constituting the magnetic wall moving spatial light modulation element 600b arranged on a straight line are shown. One is shown respectively.

In the domain wall moving type space light modulation element 600a to be the first pixel, the first ferromagnetic exchange coupling portion A is the first ferromagnetic layers 601a and 602 made of a ferromagnetic material and the first ferromagnetic layers 601a and 602. The second ferromagnetic layers 604a and 604c, which are formed on the surface and are made of a ferromagnetic material and are ferromagnetically exchange-coupled with the first ferromagnetic layers 601a and 602, and through-hole electrodes 611 and 614 are provided. Further, a transparent electrode layer 610a is provided on the surface of the second ferromagnetic layers 604a and 604c opposite to the first ferromagnetic layers 601a and 602.

In the first ferromagnetic exchange coupling portion A of the domain wall moving type spatial light modulation element 600a, through-hole electrodes 611 and 614 are arranged between the first ferromagnetic layers 601a and 602 and the second ferromagnetic layers 604a and 604c. Has been done.

In the domain wall moving type space optical modulation element 600a, the second ferromagnetic exchange coupling portion B is formed on the first ferromagnetic layers 601a and 602 and the first ferromagnetic layers 601a and 602 made of a ferromagnetic material, and is strong. The second ferromagnetic layers 604a and 604c, which are made of a magnetic material and are ferromagnetically exchange-coupled with the first ferromagnetic layers 601a and 602, and through-hole electrodes 612 and 613 are provided. Further, a transparent electrode layer 610a is provided on the surface of the second ferromagnetic layers 604a and 604c opposite to the first ferromagnetic layers 601a and 602.

In the second ferromagnetic exchange coupling portion B of the domain wall moving type spatial light modulation element 600a, through-hole electrodes 612 and 613 are arranged between the second ferromagnetic layers 604a and 604c and the transparent electrode layer 610a.

In the domain wall moving type space light modulation element 600b to be the second pixel, the first ferromagnetic exchange coupling portion A is the first ferromagnetic layers 601b and 602 made of a ferromagnetic material and the first ferromagnetic layers 601b and 602. The second ferromagnetic layers 604b and 604d, which are formed on the surface and are made of a ferromagnetic material and are ferromagnetically exchange-coupled with the first ferromagnetic layers 601b and 602, and through-hole electrodes 611 and 617 are provided. Further, a transparent electrode layer 610b is provided on the surface of the second ferromagnetic layers 604b and 604d opposite to the first ferromagnetic layers 601b and 602.

In the first ferromagnetic exchange coupling portion A of the domain wall moving type spatial light modulation element 600b, through-hole electrodes 611 and 617 are arranged between the first ferromagnetic layers 601b and 602 and the second ferromagnetic layers 604b and 604d. Has been done.

In the domain wall moving type space optical modulation element 600b, the second ferromagnetic exchange coupling portion B is formed on the first ferromagnetic layers 601b and 602 and the first ferromagnetic layers 601b and 602 made of a ferromagnetic material, and is strong. The second ferromagnetic layers 604b and 604d, which are made of a magnetic material and are ferromagnetically exchange-coupled with the first ferromagnetic layers 601b and 602, and through-hole electrodes 615 and 616 are provided. Further, a transparent electrode layer 610b is provided on the surface of the second ferromagnetic layers 604b and 604d opposite to the first ferromagnetic layers 601b and 602.

In the second ferromagnetic exchange coupling portion B of the domain wall moving type spatial light modulation element 600b, through-hole electrodes 615 and 616 are arranged between the second ferromagnetic layers 604b and 604d and the transparent electrode layer 610b.

Then, in the domain wall moving type spatial light modulation elements 600a and 600b, the first ferromagnetic layers 601a, 601b, and 602, the second ferromagnetic layers 604a, 604b, 604c, and 604d, and the through-hole electrodes 611, 612, 613, 614 , 615, 616, and 617, and the parts other than the transparent electrode layers 610a and 610b are formed of the insulating material 606.

Further, in the domain wall moving type spatial light modulation element 600a, the pulse current can be applied by connecting the pulse current source 609a to the first ferromagnetic layers 601a and 602. Further, in the domain wall moving type spatial light modulation element 600b, a pulse current can be applied by connecting the pulse current source 609b to the first ferromagnetic layer 601b and 602.

[First ferromagnetic exchange coupling part]
One light modulator constituting the magnetic wall moving space light modulation element 600a arranged linearly on the FF'cross section of the magnetic wall moving space light modulation element (600a + 600b) shown in FIG. 6B. And one light modulator constituting the magnetic wall moving type spatial light modulation element 600b are shown. Then, one first ferromagnetic exchange coupling portion A is arranged between the two second ferromagnetic exchange coupling portions B arranged at both ends of the optical modulation portion C.

Another light modulation constituting the magnetic wall moving space light modulation element 600a arranged linearly on the GG'cross section of the magnetic wall moving space light modulation element (600a + 600b) shown in FIG. 6C. A body and another light modulator that constitutes the magnetic wall moving spatial light modulator 600b are shown. Then, one first ferromagnetic exchange coupling portion B is arranged between the two second ferromagnetic exchange coupling portions A arranged at both ends of the optical modulation portion C.

Then, in each of the light modulators constituting the domain wall moving type spatial light modulation element (600a + 600b), the upper surfaces of the light modulation unit C, the first ferromagnetic exchange coupling portion A, and the second ferromagnetic exchange coupling portion B are continuous. It is formed flush with each other.

(First ferromagnetic layer)
In the second embodiment of the present invention shown in FIG. 6B, the first ferromagnetic layer 602 in the first ferromagnetic exchange coupling portion A of the domain wall moving spatial light modulation element 600a is formed under the second ferromagnetic layer 604a. Has been done. Further, in FIG. 6C, the first ferromagnetic layer 601a in the first ferromagnetic exchange coupling portion A of the domain wall moving spatial light modulation element 600a is formed under the second ferromagnetic layer 604c.

In the second embodiment of the present invention shown in FIG. 6B, the first ferromagnetic layer 602 in the first ferromagnetic exchange coupling portion A of the domain wall moving spatial light modulation element 600b is formed under the second ferromagnetic layer 604b. Has been done. Further, in FIG. 6C, the first ferromagnetic layer 601b in the first ferromagnetic exchange coupling portion A of the domain wall moving spatial light modulation element 600b is formed under the second ferromagnetic layer 604d.

Further, as shown in FIGS. 6A to 6C, in the magnetic domain wall moving type spatial light modulation element 600a according to the second embodiment of the present invention, the pulse current source 609a is connected to the first ferromagnetic layer 601a and 602. By doing so, it is possible to apply a pulse current. Further, in the domain wall moving type spatial light modulation element 600b, a pulse current can be applied by connecting the pulse current source 609b to the first ferromagnetic layer 601b and 602.

(Second ferromagnetic layer)
In the second embodiment of the present invention shown in FIG. 6B, the second ferromagnetic layer 604a in the first ferromagnetic exchange coupling portion A of the magnetic domain wall moving spatial light modulation element 600a is formed on the first ferromagnetic layer 602. Has been done. Further, in FIG. 6C, the second ferromagnetic layer 604c in the first ferromagnetic exchange coupling portion A of the domain wall moving spatial light modulation element 600a is formed on the first ferromagnetic layer 601a.

In the second embodiment of the present invention shown in FIG. 6B, the second ferromagnetic layer 604b in the first ferromagnetic exchange coupling portion A of the magnetic domain wall moving spatial light modulation element 600b is formed on the first ferromagnetic layer 602. Has been done. Further, in FIG. 6C, the second ferromagnetic layer 604d in the first ferromagnetic exchange coupling portion A of the domain wall moving spatial light modulation element 600b is formed on the first ferromagnetic layer 601b.

(Through hole electrode)
In the second embodiment of the present invention shown in FIG. 6B, in the first ferromagnetic exchange coupling portion A of the domain wall moving type spatial light modulation element 600a, the through-hole electrode 611 has the first ferromagnetic layer 602 and the second strong. It is arranged between the magnetic layer 604a and the magnetic layer 604a. Further, in FIG. 6C, the through-hole electrode 614 in the first ferromagnetic exchange coupling portion A of the domain wall moving spatial light modulation element 600a is arranged between the first ferromagnetic layer 601a and the second ferromagnetic layer 604c. There is.

In the second embodiment of the present invention shown in FIG. 6B, in the first ferromagnetic exchange coupling portion A of the magnetic domain wall moving type spatial light modulation element 600b, the through-hole electrode 611 has the first ferromagnetic layer 602 and the second strong. It is arranged between the magnetic layer 604b and the magnetic layer 604b. Further, in FIG. 6C, the through-hole electrode 617 in the first ferromagnetic exchange coupling portion A of the magnetic domain wall moving spatial light modulation element 600b is arranged between the first ferromagnetic layer 601b and the second ferromagnetic layer 604d. There is.

In the magnetic wall moving type spatial light modulation element (600a + 600b) according to the second embodiment, the through-hole electrodes 611, 612, 613, 614, 615, 616, and 617 are formed in a layer made of an insulating member 606, and the magnetic wall. The mobile spatial light modulation elements 600 are stacked and arranged at predetermined positions.

[Second ferromagnetic exchange coupling part]
As described above, the domain wall moving spatial light modulation element (600a + 600b) according to the second embodiment of the present invention shown in FIG. 6B is linearly arranged on the FF'cross section. One optical modulator constituting the element 600a and one optical modulator constituting the domain wall moving spatial light modulator 600b are shown, and one first ferromagnetic exchange coupling portion A is optically modulated. It is arranged between two second ferromagnetic exchange coupling portions B arranged at both ends of the portion C.

Further, the magnetic wall moving spatial light modulation element 600a is linearly arranged on the GG'cross section of the magnetic wall moving spatial light modulation element (600a + 600b) according to the second embodiment of the present invention shown in FIG. 6C. Another light modulator constituting the above and another optical modulator constituting the domain wall moving spatial light modulation element 600b are shown, and one first ferromagnetic exchange coupling portion B is optical modulation. It is arranged between two second ferromagnetic exchange coupling parts A arranged at both ends of the part C.

Then, in each of the light modulators constituting the domain wall moving type spatial light modulation element (600a + 600b), the upper surfaces of the light modulation unit C, the first ferromagnetic exchange coupling portion A, and the second ferromagnetic exchange coupling portion B are continuous. It is formed flush with each other.

(First ferromagnetic layer)
In the second embodiment of the present invention shown in FIG. 6B, the first ferromagnetic layer 601b in the second ferromagnetic exchange coupling portion B of the magnetic domain wall moving spatial light modulation element 600a is formed under the second ferromagnetic layer 604a. Has been done. Further, in FIG. 6C, the first ferromagnetic layer 602 in the second ferromagnetic exchange coupling portion B of the domain wall moving spatial light modulation element 600a is formed under the second ferromagnetic layer 604c.

In the second embodiment of the present invention shown in FIG. 6B, the first ferromagnetic layer 602 in the first ferromagnetic exchange coupling portion B of the magnetic domain wall moving spatial light modulation element 600b is formed under the second ferromagnetic layer 604b. Has been done. Further, in FIG. 6C, the first ferromagnetic layer 602 in the second ferromagnetic exchange coupling portion B of the domain wall moving spatial light modulation element 600b is formed under the second ferromagnetic layer 604d.

(Second ferromagnetic layer)
In the second embodiment of the present invention shown in FIG. 6B, the second ferromagnetic layer 604a in the second ferromagnetic exchange coupling portion B of the domain wall moving spatial light modulation element 600a is formed on the first ferromagnetic layer 601a. Has been done. Further, in FIG. 6C, the second ferromagnetic layer 604c in the second ferromagnetic exchange coupling portion B of the magnetic domain wall moving type spatial light modulation element 600a is formed on the first ferromagnetic layer 602.

In the second embodiment of the present invention shown in FIG. 6B, the second ferromagnetic layer 604b in the second ferromagnetic exchange coupling portion B of the magnetic domain wall moving spatial light modulation element 600b is formed on the first ferromagnetic layer 601b. Has been done. Further, in FIG. 6C, the second ferromagnetic layer 604d in the second ferromagnetic exchange coupling portion B of the magnetic domain wall moving spatial light modulation element 600b is formed on the first ferromagnetic layer 602.

(Through hole electrode)
In the second embodiment of the present invention shown in FIG. 6B, in the second ferromagnetic exchange coupling portion B of the magnetic domain wall moving type spatial light modulation element 600a, the through-hole electrode 612 is the second ferromagnetic layer 604a and the transparent electrode layer 610a. It is placed between and. Further, in FIG. 6C, the through-hole electrode 613 in the second ferromagnetic exchange coupling portion B of the magnetic wall moving type spatial light modulation element 600a is arranged between the second ferromagnetic layer 604c and the transparent electrode layer 610a.

In the second embodiment of the present invention shown in FIG. 6B, in the second ferromagnetic exchange coupling portion B of the magnetic domain wall moving spatial light modulation element 600b, the through-hole electrode 615 is the second ferromagnetic layer 604b and the transparent electrode layer 610b. It is placed between and. Further, in FIG. 6C, the through-hole electrode 616 in the second ferromagnetic exchange coupling portion B of the magnetic domain wall moving type spatial light modulation element 600b is arranged between the second ferromagnetic layer 604d and the transparent electrode layer 610b.

[Optical modulator]
In the four light modulators constituting the domain wall movable spatial light modulation element (600a + 600b) according to the second embodiment shown in FIGS. 6A to 6C, the light modulation unit C has a flat plate shape (rectangular shape) extending in a predetermined direction. The first ferromagnetic exchange coupling portion A and the second ferromagnetic exchange coupling portion B are arranged at both ends thereof. The optical modulation section C and the upper surfaces of the first ferromagnetic exchange coupling section A and the second ferromagnetic exchange coupling section B are continuously formed to be flush with each other.

That is, in the four optical modulators constituting the domain wall moving space optical modulator (600a + 600b) according to the second embodiment, the optical modulator C is a continuous layer of the second ferromagnetic layer 604a, a continuous layer of 604b, and 604c. In each photomodulator, the second ferromagnet in the first ferromagnet exchange coupling part A and the second ferromagnetism in the second ferromagnetism exchange coupling part B are formed as a continuous layer of 604d and a continuous layer of 604d. It is configured as the same layer as the layer.

Further, the magnetic wall moving type spatial light modulation element (600a + 600b) according to the second embodiment includes four light modulators having a substantially rectangular light modulation unit C, and two light modulations are provided in each of the first directions. The bodies are arranged in two rows in the second direction so that the long sides of the rectangle are substantially parallel. Then, at the end of the optical modulators in the adjacent rows, the first ferromagnetic exchange coupling portion and the second ferromagnetic exchange coupling portion are alternately arranged, and in the optical modulators in the adjacent rows, the first strong The first ferromagnetic layer of the magnetic exchange coupling portion and the second ferromagnetic exchange coupling portion is shared.

The magnetic wall movable spatial light modulation element (600a + 600b) according to the second embodiment is a magnetic wall in which the aperture ratio is further improved without increasing the drive current by arranging the elements corresponding to two pixels in the above configuration. A mobile spatial light modulation element can be realized.

Further, in the magnetic wall moving type spatial light modulation element (600a + 600b) according to the second embodiment, in the adjacent light modulator, the first ferromagnetism of the first ferromagnetism exchange coupling portion and the second ferromagnetism exchange coupling portion intervening. By sharing the layers, the aperture ratio of the domain wall movable spatial light modulation element can be further improved.

[Transparent electrode layer]
In the magnetic domain wall moving type spatial light modulation element (600a + 600b) according to the second embodiment shown in FIGS. 6A to 6C, the transparent electrode layers 610a and 610b are placed on the second ferromagnetic layers 604a, 604b, 604c and 604d. , The first ferromagnetic layers 601a, 601b, 602 are arranged on the opposite surface.

(Drive current)
In FIGS. 6A to 6C, the drive current 605a in the magnetic domain wall moving space optical modulation element 600a according to the second embodiment is the first ferromagnetic exchange coupling portion A in the FF'cross-sectional view shown in FIG. 6B. It enters the second ferromagnetic layer 604a from the first ferromagnetic layer 602 and moves from right to left in the optical modulation layer C. After that, when it reaches the second ferromagnetic exchange coupling portion B, it enters the transparent electrode layer 610a through the through-hole electrode 612, and moves by folding back from left to right inside the transparent electrode layer 610a.

Subsequently, the drive current 605a in the domain wall moving type space optical modulation element 600a is passed through the end portion of the adjacent optical modulator from the transparent electrode layer 610a as shown in the GG'cross section shown in FIG. 6C. It enters the second ferromagnet layer 604c of the second ferromagnet exchange coupling portion B through the hole electrode 613, moves from right to left in the photomodulation layer C, and first ferromagnetism at the end of the photomodulation layer C. After reaching the exchange coupling portion A, it flows out from the first ferromagnetic layer 601a of the first ferromagnetic exchange coupling portion A.

Similarly, the drive current 605b in the domain wall moving space optical modulation element 600b according to the second embodiment is the first ferromagnetism of the first ferromagnetism exchange coupling portion A in the FF'cross-sectional view shown in FIG. 6B. It enters the second ferromagnetic layer 604b from the layer 602 and moves from left to right in the optical modulation layer C. After that, when it reaches the second ferromagnetic exchange coupling portion B, it enters the transparent electrode layer 610b through the through-hole electrode 615, and moves by turning back from right to left inside the transparent electrode layer 610b.

Subsequently, the drive current 605b in the domain wall moving type space optical modulation element 600b is passed through the end portion of the adjacent optical modulator from the transparent electrode layer 610b as shown in the GG'cross-sectional view shown in FIG. 6C. It enters the second ferromagnet layer 604d of the second ferromagnet exchange coupling portion B through the hole electrode 616, moves from left to right in the photomodulation layer C, and first ferromagnetism at the end of the photomodulation layer C. After reaching the exchange coupling portion A, it flows out from the first ferromagnetic layer 601b of the first ferromagnetic exchange coupling portion A.

[Magnetic characteristics]
The magnetic characteristics of the domain wall movable spatial light modulation element (600a + 600b) according to the second embodiment will be described below.

Looking at the first ferromagnetism exchange coupling part A using the transparent electrode layer 610a in the domain wall moving type space light modulation element 600a, as shown in FIG. 6B, the second ferromagnetism in the first ferromagnetism exchange coupling part A The layer 604a is formed on the first ferromagnetic layer 602, and as shown in FIG. 6C, the second ferromagnetic layer 604c in the first ferromagnetic exchange coupling portion A is the first ferromagnetic layer 601a. Formed on top. The second ferromagnetic layer 604a and the layer 604c are ferromagnetically exchange-coupled with the first ferromagnetic layers 602 and 601a.

Similarly, looking at the second ferromagnetic exchange coupling portion B using the transparent electrode layer 610a in the domain wall moving space optical modulation element 600a, as shown in FIG. 6B, the first ferromagnetic exchange coupling portion B The second ferromagnetic layer 604a is formed on the first ferromagnetic layer 601a, and as shown in FIG. 6C, the second ferromagnetic layer 604c in the second ferromagnetic exchange coupling portion B is the first strong. It is formed on the magnetic layer 602. The second ferromagnetic layer 604a and the layer 604c are ferromagnetically exchange-coupled with the first ferromagnetic layers 601a and 602.

Then, based on the above-mentioned domain wall generation mechanism, the domain walls 603a and 603c are formed in the optical modulation units C of the two light modulators constituting the mobile spatial light modulation element 600a by utilizing the formed ferromagnetic exchange coupling. As a result, it functions as a domain wall moving type spatial light modulation element.

Specifically, in the magnetic wall moving type spatial light modulation element 600a, in the light modulation section of the light modulator shown as the FF'cross-sectional view in FIG. 6B, the magnetization direction of the first ferromagnetic exchange coupling section A is upward. On the other hand, the magnetization direction of the second ferromagnetic exchange coupling portion B is designed to be downward.

Further, in the magnetic wall moving type spatial light modulation element 600a, in the light modulation section of the light modulator shown as a GG'cross section in FIG. 6C, the magnetization direction of the first ferromagnetic exchange coupling section A is designed to be downward. On the other hand, the magnetization direction of the second ferromagnetic exchange coupling portion B is designed to be upward.

The domain wall 603a and 603c extending on a plane orthogonal to the direction connecting the two ferromagnetic exchange coupling portions are formed in the domain wall C of each optical modulator in the domain wall moving space optical modulation element 600a. The magnetization directions of the magnetic domains formed on both sides of 603a and 603c are opposite to each other. By forming the light modulation section C having such magnetic walls 603a and 603c, it can function as a magnetic wall moving type spatial light modulation element.

That is, in the domain wall moving type space photomodulator 600a, in the photomodulator of the photomodulator shown as the FF'cross-sectional view in FIG. 6B, the magnetic domain on the first ferromagnetic exchange coupling part A side of the domain wall 603a. The magnetization direction D61 is downward, and the magnetization direction D62 of the magnetic domain on the second ferromagnetic exchange coupling portion B side with respect to the domain wall 603a is upward.

Further, in the domain wall moving type space optical modulation element 600a, in the optical domain of the optical modulator shown as a GG'cross section in FIG. 6C, the magnetic domain on the first ferromagnetic exchange coupling portion A side of the domain wall 603c. The magnetization direction D66 is upward, and the magnetization direction D65 of the magnetic domain on the second ferromagnetic exchange coupling portion B side with respect to the domain wall 603c is downward.

Similarly, by forming the domain walls 603b and 603d in the optical modulation section C of the two light modulators constituting the mobile spatial light modulation element 600b based on the above-mentioned domain wall generation mechanism, the domain wall mobile spatial light modulation Make it function as an element.

Specifically, in the magnetic wall moving type spatial light modulation element 600b, in the light modulation portion of the light modulator shown as the FF'cross-sectional view in FIG. 6B, the magnetization direction of the first ferromagnetic exchange coupling portion A is upward. On the other hand, the magnetization direction of the second ferromagnetic exchange coupling portion B is designed to be downward.

Further, in the magnetic wall moving type spatial light modulation element 600b, in the light modulation section of the light modulator shown as a GG'cross section in FIG. 6C, the magnetization direction of the first ferromagnetic exchange coupling section A is designed to be downward. On the other hand, the magnetization direction of the second ferromagnetic exchange coupling portion B is designed to be upward.

Domain walls 603b and 603d extending on a plane orthogonal to the direction connecting the two ferromagnetic exchange coupling portions are formed in the photomodulator C of each photomodulator in the domain wall movable spatial photomodulator 600b, and the domain wall is formed. The magnetization directions of the magnetic domains formed on both sides of 603b and 603d are opposite to each other. By forming the optical modulation unit C having such domain walls 603b and 603d, it can function as a domain wall moving type spatial light modulation element.

That is, in the domain wall moving type spatial photomodulator 600b, in the photomodulator of the photomodulator shown as the FF'cross section in FIG. 6B, the magnetic domain on the first ferromagnetic exchange coupling part A side of the domain wall 603b. The magnetization direction D63 is downward, and the magnetization direction D64 of the magnetic domain on the second ferromagnetic exchange coupling portion B side with respect to the domain wall 603b is upward.

Further, in the domain wall moving type space optical modulator 600b, in the optical domain of the optical modulator shown as a GG'cross section in FIG. 6C, the magnetic domain on the first ferromagnetic exchange coupling portion A side of the domain wall 603d. The magnetization direction D68 is upward, and the magnetization direction D67 of the magnetic domain on the second ferromagnetic exchange coupling portion B side with respect to the domain wall 603d is downward.

<Magnetic wall moving spatial light modulator>
The domain wall moving space light modulator of the present invention is a domain wall moving space light modulator including a plurality of the above-mentioned domain wall moving space light modulators, and the plurality of domain wall moving space light modulators are in the first direction. And the second direction orthogonal to the first direction, and arranged in a grid pattern.

The domain wall moving spatial light modulator of the present invention includes the domain wall moving spatial light modulator 90 (shown in FIGS. 1A to 1C) described in Patent Document 2 and the domain wall moving spatial light modulator 100 described in Patent Document 3. And 200 (shown in FIGS. 2A to 2B), and the domain wall moving spatial light modulator 400 (shown in FIG. 3) described in Patent Document 4 can have the same configuration.

Therefore, the domain wall moving spatial light modulators described in Patent Documents 2 to 4 will be described below.

FIG. 1C is a top view showing the configuration of the domain wall movable spatial light modulator 90 described in Patent Document 2. As shown in FIG. 1C, the domain wall moving type spatial light modulation elements 91 according to Patent Document 2 are independently manufactured and arranged on a substrate (not shown). In the domain wall movable spatial light modulator of the present invention, for example, the above configuration can be adopted.

2A is a top view of the domain wall moving spatial light modulator 100 described in Patent Document 3, and FIG. 2B is a top view of the domain wall moving spatial light modulator 200 described in Patent Document 3. is there.

In the domain wall moving spatial light modulator 100 shown in FIG. 2A, the plurality of domain wall moving spatial light modulators 10 are independently manufactured and arranged on a substrate (not shown). The domain wall moving type spatial light modulation element 10 includes a light modulation region 300, a first magnetization fixing layer 11a, and a second magnetization fixing layer 21.

Similarly, in the domain wall moving spatial light modulator 200 shown in FIG. 2B, the plurality of domain wall moving spatial light modulators 20 are independently manufactured and arranged on a substrate (not shown). The domain wall moving type spatial light modulation element 20 includes a light modulation region 300, a first magnetization fixing layer 11b, and a second magnetization fixing layer 21.

In the domain wall moving space optical modulator 100 shown in FIG. 2A, the first ferromagnetic layer (that is, the first magnetization fixed layer 11a) of the first ferromagnetic exchange coupling portion has a direction in which both ferromagnetic exchange coupling portions extend. ) Is longer than the first ferromagnetic layer (that is, the second magnetization fixed layer 21a) of the second ferromagnetic exchange coupling portion. Further, the plurality of domain wall moving type spatial light modulation elements 10 are arranged in a grid pattern, and share the first magnetization fixing layer 11a with other domain wall moving type spatial light modulation elements 10 arranged in the extending direction.

In the domain wall moving space optical modulator 100 shown in FIG. 2A, the first magnetization fixing layer 11a is longer in the extending direction than the second magnetization fixing layer 21, so that the first magnetization fixing layer 11a is the second. The coercive force is smaller than that of the magnetized fixed layer 21, and as a result, a coercive force difference is generated between the two. In the domain wall movable spatial light modulator of the present invention, for example, the above configuration can be adopted.

In the domain wall moving space light modulator 200 shown in FIG. 2B, in the optical modulation section of the domain wall moving space light modulator 100 shown in FIG. 2A, the optical modulation section of two adjacent domain wall moving space light modulation elements. However, they are connected and configured on the first ferromagnetic layer.

As a result, the first ferromagnetic layer (first magnetization fixed layer 11b) in the first ferromagnetic exchange coupling portion 1 has a long shape, so that the first ferromagnetic layer (second magnetic exchange coupling portion 2) in the second ferromagnetic exchange coupling portion 2 has a long shape. A difference in coercive force can be provided due to the difference in shape from the magnetization fixing layer 21). Further, since the first magnetization fixed layer 11b can be further miniaturized, the aperture ratio of the domain wall movable spatial light modulator can be further improved. In the domain wall movable spatial light modulator of the present invention, for example, the above configuration can be adopted.

FIG. 3 is a top view of the domain wall movable spatial light modulator 400 described in Patent Document 4. In the domain wall movable spatial light modulator 400 shown in FIG. 3, a plurality of domain wall movable spatial light modulators 40 are independently manufactured and arranged on a substrate (not shown). The domain wall moving type spatial light modulation element 40 includes a light modulation region 300, a first magnetization fixing layer 11c, and a second magnetization fixing layer 21.

In the domain wall moving spatial light modulator 400 shown in FIG. 3, the first ferromagnetic layer (first magnetization fixed layer 11c) in the first ferromagnetic exchange coupling portion 1 is adjacent to two magnetic domain moving spatial light modulators. It is shared and configured among the elements 40. With this configuration, the distance between adjacent elements can be narrowed to increase the effective optical modulation region, and the aperture ratio can be improved. In the domain wall movable spatial light modulator of the present invention, for example, the above configuration can be adopted.

1, A 1st ferromagnetic exchange coupling part 2, B 2nd ferromagnetic exchange coupling part 3, C optical modulation part 9, 59, 69, 509, 609a, 609b Pulse current source 10, 20, 40, 50, 60, 91, 500, 600a, 600b Magnetic wall moving type space optical modulation element 11, 11a, 11b, 51, 61, 62, 501, 602 1st magnetization fixed layer (1st ferromagnetic layer)
12, 22 Non-magnetic metal layer 13, 23 Buffer layer 21, 52, 62, 502, 601a, 601b Second magnetization fixed layer (first ferromagnetic layer)
30, 54, 64, 504a, 504b, 604a, 604b, 604c, 604d Optical modulation layer (second ferromagnetic layer)
31, 32 Magnetic domain 31a, 32a Initial domain 33, 53, 63, 503a, 503b, 603a, 603b, 603c, 603d Domain wall 90, 100, 200 Domain wall mobile spatial light modulator 300 Optical modulation area 55, 65, 505, 605a , 605b Drive current 506, 606 Insulation member 510, 610a, 610b Transparent electrode layer 511, 512, 513, 514, 611, 612, 613, 614, 615, 616, 617 Through-hole electrode D1, D3, D51, D53, D61 , D63, D65, D67 Magnetization direction (downward)
D2, D4, D52, D54, D62, D64, D66, D68 Magnetization direction (upward)

Claims (5)

An optical modulator that changes the direction of polarized light of incident light and emits it,
The first ferromagnetic exchange coupling portion and the second ferromagnetic exchange coupling portion, which are arranged at both ends of the optical modulation section and have different coercive forces,
It is a domain wall moving type spatial light modulation element provided with a plurality of light modulators having the above.
Both the first ferromagnetic exchange coupling portion and the second ferromagnetic exchange coupling portion
The first ferromagnetic layer made of ferromagnetic material and
A second ferromagnetic layer formed on the first ferromagnetic layer and made of a ferromagnetic material to be ferromagnetically exchange-coupled with the first ferromagnetic layer,
With through-hole electrodes,
A transparent electrode layer is provided on the surface of the second ferromagnetic layer opposite to the first ferromagnetic layer.
In the first ferromagnetic exchange coupling portion, the through-hole electrode is arranged between the first ferromagnetic layer and the second ferromagnetic layer.
In the second ferromagnetic exchange coupling portion, a magnetic wall moving type spatial light modulation element in which the through-hole electrode is arranged between the second ferromagnetic layer and the transparent electrode layer. The optical modulator is substantially rectangular, the long sides are arranged substantially parallel, and in the adjacent optical modulator, the first ferromagnetic exchange coupling portion and the second ferromagnetic exchange coupling portion are Arranged alternately,
The magnetic domain wall moving space according to claim 1, wherein in the adjacent optical modulators, the first ferromagnetic exchange coupling portion and the first ferromagnetic layer of the second ferromagnetic exchange coupling portion are shared. Light modulation element. An optical modulator that changes the direction of polarized light of incident light and emits it,
The first ferromagnetic exchange coupling and the second ferromagnetic exchange coupling, which have different coercive forces,
A magnetic wall moving type spatial light modulation element including a light modulator having the above.
In the domain wall moving type spatial light modulation element,
Two of the first ferromagnetic exchange couplings are arranged at both ends of the optical modulation section, and one second ferromagnetic exchange coupling is interposed between the two first ferromagnetic exchange couplings. Be placed or
Two said second ferromagnetic exchange couplings are arranged at both ends of the optical modulation section, and one said first ferromagnetic exchange coupling is interposed between the two said second ferromagnetic exchange couplings. Have been placed and
Both the first ferromagnetic exchange coupling portion and the second ferromagnetic exchange coupling portion
The first ferromagnetic layer made of ferromagnetic material and
A second ferromagnetic layer formed on the first ferromagnetic layer and made of a ferromagnetic material to thermally exchange and bond with the first ferromagnetic layer,
With through-hole electrodes,
A transparent electrode layer is provided on the surface of the second ferromagnetic layer opposite to the first ferromagnetic layer.
In the first ferromagnetic exchange coupling portion, the through-hole electrode is arranged between the first ferromagnetic layer and the second ferromagnetic layer.
In the second ferromagnetic exchange coupling portion, a magnetic wall moving type spatial light modulation element in which the through-hole electrode is arranged between the second ferromagnetic layer and the transparent electrode layer. The domain wall movable spatial light modulation element includes a plurality of the light modulators.
The optical modulator is substantially rectangular, has long sides arranged substantially parallel, and in the optical modulator in an adjacent row, the first ferromagnetic exchange coupling portion and the second ferromagnetic exchange coupling portion. And are arranged alternately,
The domain wall movement according to claim 3, wherein in the light modulators in adjacent rows, the first ferromagnetic exchange coupling portion and the first ferromagnetic layer of the second ferromagnetic exchange coupling portion are shared. Type spatial light modulation element. A magnetic wall mobile spatial light modulator comprising the domain wall mobile spatial light modulator according to any one of claims 1 to 4.
A magnetic wall moving spatial light modulator in which a plurality of the domain wall moving spatial light modulators are arranged in a grid pattern in a first direction and a second direction orthogonal to the first direction.

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