JP2021190690A - Domain wall moving element and magnetic recording array - Google Patents

Abstract

To provide a reliable domain wall moving element and a magnetic recording array.SOLUTION: In a domain wall moving element according to an embodiment, a first ferromagnetic layer, a non-magnetic layer, and a second ferromagnetic layer are laminated in this order from the side closer to a substrate, and in the cut surface cut along a second direction orthogonal to a first direction in which the first ferromagnetic layer extends in a plan view from the stacking direction, the shortest width of the first ferromagnetic layer in the second direction is shorter than the width of the non-magnetic layer in the second direction.SELECTED DRAWING: Figure 5

Description

The present invention relates to a domain wall moving element and a magnetic recording array.

Next-generation non-volatile memory is attracting attention as an alternative to flash memory, etc., whose miniaturization has reached its limit. For example, MRAM (Magnetoresistive Random Access Memory), ReRAM (Resistance Random Access Memory), PCRAM (Phase Change Random Access Memory), and the like are known as next-generation non-volatile memory.

The MRAM utilizes the change in resistance value caused by the change in the direction of magnetization for data recording. Data recording is carried out by each of the magnetoresistance changing elements constituting the MRAM. For example, Patent Document 1 describes a three-terminal type magnetoresistive element that separates a write current and a read current path.

Japanese Patent No. 6275806

When the magnetoresistive sensor is miniaturized, a process called slimming may be performed. Slimming is a process of irradiating the side surface of the magnetoresistive sensor with an ion beam to reduce the planar viewing area of the magnetoresistive sensor. However, when the exposed metal surface of the ion beam is irradiated, a part of the metal may be scattered and reattached to the side wall of the magnetoresistive sensor. The impurities adhering to the side wall of the magnetoresistive sensor deteriorate the magnetic properties of the ferromagnet constituting the magnetoresistive sensor. The attached impurities also cause leakage of the magnetoresistive sensor. The impurities adhering to the side wall of the magnetoresistive sensor reduce the reliability of the magnetoresistive sensor.

The present invention has been made in view of the above problems, and provides a highly reliable magnetoresistive sensor and a magnetic recording array.

(1) The domain wall moving element according to the first aspect is laminated in the order of the first ferromagnetic layer, the non-magnetic layer, and the second ferromagnetic layer from the side closer to the substrate, and the first strength is seen in a plan view from the lamination direction. In the cut surface cut along the second direction orthogonal to the first direction in which the magnetic layer extends, the shortest width of the first ferromagnetic layer in the second direction is larger than the width of the non-magnetic layer in the second direction. short.

(2) In the cut surface along the stacking direction and the second direction of the domain wall moving element according to the above aspect, the side surface of the first ferromagnetic layer may be inclined with respect to the stacking direction.

(3) In the cut surface along the stacking direction and the second direction of the magnetic wall moving element according to the above aspect, the side surface of the first ferromagnetic layer has a first inclined surface and a second inclined surface, and is the first. The inclined surface is inclined from the lower end of the first ferromagnetic layer on the side close to the substrate toward the center of the first ferromagnetic layer in the second direction, and the second inclined surface is the first ferromagnetic layer. It may be inclined from the upper end on the side far from the substrate toward the center of the first ferromagnetic layer in the second direction.

(4) In the domain wall moving element according to the above aspect, the width of the first surface of the first ferromagnetic layer on the non-magnetic layer side in the second direction is shorter than the width of the non-magnetic layer in the second direction. You may.

(5) In the domain wall moving element according to the above aspect, the position where the width of the first ferromagnetic layer in the second direction is the shortest is on the non-magnetic layer side from the center of the first ferromagnetic layer in the stacking direction. May be there.

(6) In the domain wall moving element according to the above aspect, the longest width of the first ferromagnetic layer in the second direction may be shorter than the width of the non-magnetic layer in the second direction.

(7) In the domain wall moving element according to the above aspect, the width of the second surface of the first ferromagnetic layer on the side far from the non-magnetic layer is the width of the non-magnetic layer in the second direction. It may be longer.

(8) In the domain wall moving element according to the above aspect, the thickness of the non-magnetic layer may be 30 Å or more.

(9) In the domain wall moving element according to the above aspect, the milling rate of the non-magnetic layer may be slower than the milling rate of the first ferromagnetic layer.

(10) The domain wall moving element according to the above aspect further includes a base layer on the opposite side of the first ferromagnetic layer to the non-magnetic layer, and the base layer has a slower milling rate than the first ferromagnetic layer. May be good.

(11) The first ferromagnetic layer of the domain wall moving element according to the above aspect contains an element constituting the base layer, and the abundance ratio of the element is the second of the first ferromagnetic layer in the stacking direction. The first region on the base layer side from the position where the width in the direction is the shortest is on the non-magnetic layer side from the position where the width in the second direction of the first ferromagnetic layer is the shortest in the stacking direction. It may be darker than the second region.

(12) The magnetic wall moving element according to the above aspect has the non-magnetic layer sandwiched in the first direction, and the first conductive portion and the second conductive portion electrically connected to the first ferromagnetic layer via the base layer. It has a conductive portion, and the width of each of the first conductive portion and the second conductive portion in the second direction is wider than the width of the first ferromagnetic layer in the second direction, and the milling of the base layer. The rate may be slower than the milling rate of the first conductive portion and the second conductive portion.

(13) The domain wall moving element according to the above aspect may further include a metal layer different from the second ferromagnetic layer on the side of the second ferromagnetic layer in the second direction.

(14) The magnetic recording array according to the second aspect has a plurality of domain wall moving elements according to the above aspect.

The domain wall moving element and the magnetic recording array according to the above aspect are excellent in reliability.

It is a block diagram of the magnetic recording array which concerns on 1st Embodiment. It is sectional drawing of the characteristic part of the magnetic recording array which concerns on 1st Embodiment. It is an xz sectional view of the domain wall moving element which concerns on 1st Embodiment. It is a top view of the domain wall moving element which concerns on 1st Embodiment. It is yz cross-sectional view in the center in the x direction of the domain wall moving element which concerns on 1st Embodiment. It is yz cross-sectional view in the 1st conductive part of the domain wall moving element which concerns on 1st Embodiment. It is a schematic diagram for demonstrating slimming at the time of manufacturing the domain wall moving element which concerns on 1st Embodiment. It is yz cross-sectional view in the center in the x direction of the domain wall moving element which concerns on 1st modification. It is yz cross-sectional view in the center in the x direction of the domain wall moving element which concerns on 2nd modification. It is a yz cross-sectional view in the center in the x direction of the domain wall moving element which concerns on 3rd modification. It is an xz sectional view of the domain wall moving element which concerns on 1st Embodiment. It is yz cross-sectional view in the center in the x direction of the domain wall moving element which concerns on 1st Embodiment.

Hereinafter, the present embodiment will be described in detail with reference to the drawings as appropriate. The drawings used in the following description may be enlarged for convenience in order to make the features of the present invention easy to understand, and the dimensional ratios of each component may differ from the actual ones. be. The materials, dimensions, and the like exemplified in the following description are examples, and the present invention is not limited thereto, and can be appropriately modified and carried out within the range in which the effects of the present invention are exhibited.

First, define the direction. The x-direction and the y-direction are directions substantially parallel to one surface of the substrate Sub (see FIG. 2) described later. The x direction is a direction in which the first ferromagnetic layer 10 described later extends, and is a direction toward the second conductive portion 52 from the first conductive portion 51 described later. The y direction is a direction orthogonal to the x direction. The z-direction is a direction from the substrate Sub, which will be described later, toward the domain wall moving element 100. The z direction is an example of the stacking direction. Further, in the present specification, "extending in the x direction" means that, for example, the dimension in the x direction is larger than the smallest dimension among the dimensions in the x direction, the y direction, and the z direction. The same applies when extending in other directions.

[First Embodiment]
FIG. 1 is a block diagram of a magnetic recording array according to the first embodiment. The magnetic recording array 200 includes a plurality of domain wall moving elements 100, a plurality of first wirings Wp1 to Wpn, a plurality of second wirings Cm1 to Cmn, a plurality of third wirings Rp1 to Rpn, and a plurality of first switching elements. It includes 110, a plurality of second switching elements 120, and a plurality of third switching elements 130. The magnetic recording array 200 can be used, for example, in a magnetic memory, a product-sum calculator, and a neuromorphic device.

<1st wiring, 2nd wiring, 3rd wiring>
The first wirings Wp1 to Wpn are write wirings. The first wirings Wp1 to Wpn electrically connect the power supply and one or more domain wall moving elements 100. The power supply is connected to one end of the magnetic recording array 200 during use.

The second wirings Cm1 to Cmn are common wirings. The common wiring is wiring that can be used both when writing data and when reading data. The second wirings Cm1 to Cmn electrically connect the reference potential and one or more domain wall moving elements 100. The reference potential is, for example, ground. The second wirings Cm1 to Cmn may be provided in each of the plurality of domain wall moving elements 100, or may be provided over the plurality of domain wall moving elements 100.

The third wirings Rp1 to Rpn are read wirings. The third wirings Rp1 to Rpn electrically connect the power supply and one or more domain wall moving elements 100. The power supply is connected to one end of the magnetic recording array 200 during use.

<1st switching element, 2nd switching element, 3rd switching element>
The first switching element 110, the second switching element 120, and the third switching element 130 shown in FIG. 1 are connected to each of the plurality of domain wall moving elements 100. The first switching element 110 is connected between each of the domain wall moving elements 100 and the first wirings Wp1 to Wpn. The second switching element 120 is connected between each of the domain wall moving elements 100 and the second wirings Cm1 to Cmn. The third switching element 130 is connected between each of the domain wall moving elements 100 and the third wirings Rp1 to Rpn.

When the first switching element 110 and the second switching element 120 are turned on, a write current flows between the first wiring Wp1 to Wpn and the second wiring Cm1 to Cmn connected to the predetermined domain wall moving element 100. When the first switching element 110 and the third switching element 130 are turned on, a read current flows between the second wirings Cm1 to Cmn and the third wirings Rp1 to Rpn connected to the predetermined domain wall moving element 100.

The first switching element 110, the second switching element 120, and the third switching element 130 are elements that control the flow of current. The first switching element 110, the second switching element 120, and the third switching element 130 are, for example, a transistor, an element such as an Ovonic Threshold Switch (OTS) that utilizes a phase change of a crystal layer, and a metal insulator transition. An element such as a (MIT) switch that utilizes a change in band structure, an element that utilizes a breakdown voltage such as a Zener diode and an avalanche diode, and an element whose conductivity changes as the atomic position changes.

Any one of the first switching element 110, the second switching element 120, and the third switching element 130 may be shared by the domain wall moving element 100 connected to the same wiring. For example, when sharing the first switching element 110, one first switching element 110 is provided upstream of the first wiring Wp1 to Wpn. For example, when sharing the second switching element 120, one second switching element 120 is provided upstream of the second wirings Cm1 to Cmn. For example, when sharing the third switching element 130, one third switching element 130 is provided upstream of the third wiring Rp1 to Rpn.

FIG. 2 is a cross-sectional view of a feature portion of the magnetic recording array 200 according to the first embodiment. FIG. 2 is a cross section of one domain wall moving element 100 in FIG. 1 cut along an xz plane passing through the center of the width of the first ferromagnetic layer 10 in the y direction.

The first switching element 110 and the second switching element 120 shown in FIG. 2 are transistors Tr. The transistor Tr has a gate electrode G, a gate insulating film GI, and a source region S and a drain region D formed on the substrate Sub. The substrate Sub is, for example, a semiconductor substrate. The third switching element 130 is electrically connected to the electrode E and is located, for example, in the depth direction (+ y direction) of the paper surface.

Each of the transistor Tr and the domain wall moving element 100 are electrically connected to each other via the wiring W. The wiring W includes a material having conductivity. The wiring W extends in the z direction, for example. The wiring W is, for example, a via wiring formed in the opening of the insulating layer In.

The domain wall moving element 100 and the transistor Tr are electrically separated by an insulating layer In except for the wiring W. The insulating layer In is an insulating layer that insulates between the wirings of the multilayer wiring and between the elements. The insulating layer In may be, for example, silicon oxide (SiO _x ), silicon nitride (SiN _x ), silicon carbide (SiC), chromium nitride, silicon carbide (SiCN), silicon oxynitride (SiON), aluminum oxide (Al ₂ O). ₃ ), zirconium oxide (ZrO _x ) and the like.

"Domain wall moving element"
FIG. 3 is a cross-sectional view of the domain wall moving element 100 cut along the xz plane passing through the center of the first ferromagnetic layer 10 in the y direction. FIG. 4 is a plan view of the domain wall moving element 100 from the z direction. FIG. 5 is a cross-sectional view taken along the yz plane passing through the center of the domain wall moving element 100 in the x direction. FIG. 5 is a cross section of the domain wall moving element 100 cut along the line AA of FIG. FIG. 6 is a cross-sectional view cut along the yz plane passing through the first conductive portion 51 of the domain wall moving element 100. FIG. 6 is a cross section of the domain wall moving element 100 cut along the line BB of FIG.

The domain wall moving element 100 has, for example, a first ferromagnetic layer 10, a second ferromagnetic layer 20, a non-magnetic layer 30, an underlayer 40, a first conductive portion 51, and a second conductive portion 52. For example, the first ferromagnetic layer 10, the non-magnetic layer 30, and the second ferromagnetic layer 20 are laminated in this order from the side closer to the substrate Sub. Another layer may be inserted between the first ferromagnetic layer 10 and the non-magnetic layer 30 and between the non-magnetic layer 30 and the second ferromagnetic layer 20. When writing data to the domain wall moving element 100, a writing current is passed through the first ferromagnetic layer 10 between the first conductive portion 51 and the second conductive portion 52. When reading data from the domain wall moving element 100, a reading current is passed between the first conductive portion 51 or the second conductive portion 52 and the second ferromagnetic layer 20.

"First ferromagnetic layer"
The first ferromagnetic layer 10 extends in the x direction. The first ferromagnetic layer 10 is energized with a write current. The first ferromagnetic layer 10 is, for example, a rectangle having a major axis in the x direction and a minor axis in the y direction in a plan view from the z direction. The first ferromagnetic layer 10 is, for example, on the substrate Sub side of the second ferromagnetic layer 20. The write current flows along the first ferromagnetic layer 10 from the first conductive portion 51 toward the second conductive portion 52, or from the second conductive portion 52 toward the first conductive portion 51.

The first ferromagnetic layer 10 is a layer capable of magnetically recording information by changing the internal magnetic state. The first ferromagnetic layer 10 may be referred to as a magnetic recording layer or a domain wall moving layer.

As shown in FIG. 3, the first ferromagnetic layer 10 has, for example, magnetized fixed regions 11 and 12 and a domain wall moving region 13. The domain wall moving region 13 is sandwiched between two magnetization fixing regions 11 and 12 in the x direction, for example.

The magnetization fixing region 11 is a region that overlaps with the first conductive portion 51 of the first ferromagnetic layer 10 when viewed from the z direction. The magnetization fixing region 12 is a region that overlaps with the second conductive portion 52 of the first ferromagnetic layer 10 when viewed from the z direction. _{The magnetizations M 11} and M ₁₂ of the magnetized fixed regions 11 and 12 are more difficult to reverse the magnetization than the magnetizations M _13A and M _{13B of} the domain wall moving region 13, and the external force of the threshold value at which _{the magnetizations M 13A} and M _{13B of the domain wall moving region 13 are reversed is applied.} Magnetization does not reverse even when applied. Therefore, it is said that _{the magnetizations M 11} and M ₁₂ of the magnetization fixing regions 11 and _{12 are fixed to the magnetizations M 13A} and M _13B of the domain wall moving region 13.

The magnetization M ₁₁ in the magnetization fixing region _{11 and the magnetization M 12 in the} magnetization fixing region 12 are oriented in different directions. The magnetization M ₁₁ in the magnetization fixing region _{11 and the magnetization M 12 in the} magnetization fixing region 12 are oriented in opposite directions, for example. Magnetization _{M 11} of the magnetization fixed regions 11 are aligned, for example, the + z direction, the magnetization _{M 12} of the magnetization fixed regions 12 are oriented in the -z direction, for example.

The domain wall moving region 13 is composed of a first magnetic domain 13A and a second magnetic domain 13B. The first magnetic domain 13A is adjacent to the magnetization fixing region 11. Magnetization _{M 13A} of the first magnetic domain 13A is influenced by the magnetization _{M 11} of the magnetization fixed regions 11, for example, oriented in the same direction as the magnetization _{M 11} of the magnetization fixed region 11. The second magnetic domain 13B is adjacent to the magnetization fixing region 12. Magnetization _{M 13B} of the second magnetic domain 13B, under the influence of the magnetization _{M 12} of the magnetization fixed regions 12, for example, oriented in the same direction as the magnetization _{M 12} of the magnetization fixed region 12. Therefore, the magnetization _{M 13B} of the magnetization _{M 13A} and the second magnetic domain 13B of the first magnetic domain 13A, oriented in different directions. The magnetization _{M 13B} of the magnetization _{M 13A} and the second magnetic domain 13B of the first magnetic domain 13A, for example, oriented in opposite directions.

The boundary between the first magnetic domain 13A and the second magnetic domain 13B is the domain wall DW. The domain wall DW moves in the domain wall moving region 13. In principle, the domain wall DW does not penetrate into the magnetization fixing regions 11 and 12.

In the domain wall moving region 13, the domain wall DW moves by passing a write current in the x direction of the domain wall moving region 13. For example, when a write current (for example, a current pulse) in the + x direction is applied to the domain wall moving region 13, electrons flow in the −x direction opposite to the current, so that the domain wall DW moves in the −x direction. When a current flows from the first magnetic domain 13A to the second magnetic domain 13B, the electrons spin-polarized in the second magnetic domain 13B reverse _{the magnetization M 13A of the first magnetic domain 13A.} By magnetization _{M 13A} of the first magnetic domain 13A is magnetization reversal, the domain wall DW moves in the -x direction. When the domain wall moves in the domain wall moving region 13, the ratio between the first magnetic domain 13A and the second magnetic domain 13B changes.

When the domain wall DW moves in the domain wall moving region 13 and the ratio between the first magnetic domain 13A and the second magnetic domain 13B changes, the resistance of the domain wall moving element 100 increases according to the ratio between the first magnetic domain 13A and the second magnetic domain 13B. Change. Further, the resistance value of the domain wall moving element 100 changes stepwise when the position of the domain wall DW is moved stepwise, and continuously changes when the position of the domain wall DW is continuously moved. The domain wall moving element 100 whose resistance value changes stepwise is suitable for handling multi-valued data. The domain wall moving element 100 whose resistance value continuously changes is suitable for handling analog data.

As shown in FIGS. 5 and 6, the shortest width L10 min in the y direction of the first ferromagnetic layer 10 is shorter than the width L30 in the y direction of the non-magnetic layer 30. The width L30 in the y direction of the non-magnetic layer 30 is an average value of the widths in the y direction, and for example, when the width in the y direction changes depending on the position in the z direction, it means these average values.

The width of the first ferromagnetic layer 10 shown in FIGS. 5 and 6 in the y direction differs depending on the position in the z direction. For example, the first surface 10a and the second surface 10b of the first ferromagnetic layer 10 have different widths in the y direction. The first surface 10a is the surface of the first ferromagnetic layer 10 on the non-magnetic layer 30 side. The second surface 10b is a surface opposite to the first surface 10a of the first ferromagnetic layer 10.

The width of the first surface 10a shown in FIGS. 5 and 6 in the y direction is the same as the width L30 of the non-magnetic layer 30 in the y direction. The width of the first ferromagnetic layer 10 shown in FIGS. 5 and 6 in the y direction narrows from the first surface 10a toward the second surface 10b, reaches the shortest width L10min, and then widens. The position where the shortest width is L10 min is, for example, the non-magnetic layer 30 side from the center of the first ferromagnetic layer 10 in the z direction. The width of the first ferromagnetic layer 10 shown in FIGS. 5 and 6 in the y direction is the longest on the second surface 10b. The width of the second surface 10b shown in FIGS. 5 and 6 in the y direction is longer than the width L30 of the non-magnetic layer 30 in the y direction. The longest width L10max of the first ferromagnetic layer 10 in the y direction is, for example, longer than the width L30 of the non-magnetic layer 30 in the y direction.

The side surface of the first ferromagnetic layer 10 shown in FIGS. 5 and 6 in the y direction is inclined in the y direction with respect to the z direction. The side surface of the first ferromagnetic layer 10 in the y direction can be divided into a first inclined surface s1 and a second inclined surface s2. The first inclined surface s1 is an inclined surface that is inclined toward the center of the first ferromagnetic layer 10 in the y direction with respect to the lower end of the side surface of the first ferromagnetic layer 10 on the substrate Sub side. The second inclined surface s2 is an inclined surface inclined toward the center in the y direction of the first ferromagnetic layer 10 with reference to the upper end of the side surface of the first ferromagnetic layer 10 on the non-magnetic layer 30 side. The second inclined surface s2 is overhanging with respect to the first inclined surface s1.

The first inclined surface s1 and the second inclined surface s2 sandwich an inflection point p1 in which the inclination of the side surface of the first ferromagnetic layer 10 with respect to the z direction is zero. The inflection point p1 is inside the end of the non-magnetic layer 30 in the y direction. The side surface of the first ferromagnetic layer 10 in the y direction is recessed with respect to a virtual surface lowered in the z direction from the end portion of the non-magnetic layer 30 in the y direction, for example.

The first ferromagnetic layer 10 is made of a magnetic material. The first ferromagnetic layer 10 preferably has at least one element selected from the group consisting of Co, Ni, Fe, Pt, Pd, Gd, Tb, Mn, Ge and Ga. Examples of the material used for the first ferromagnetic layer 10 include a Co and Ni laminated film, a Co and Pt laminated film, a Co and Pd laminated film, a MnGa-based material, a GdCo-based material, and a TbCo-based material. Ferrimagnetic materials such as MnGa-based materials, GdCo-based materials, and TbCo-based materials have a small saturation magnetization, and the threshold current required to move the domain wall DW is small. Further, the Co and Ni laminated film, the Co and Pt laminated film, and the Co and Pd laminated film have a large coercive force, and the moving speed of the domain wall DW becomes slow.

The first ferromagnetic layer 10 may contain elements constituting the base layer 40. Regarding the abundance ratio of the elements, for example, the first region R1 on the base layer 40 side from the position where the first ferromagnetic layer 10 has the shortest width L10 min in the z direction, and the first ferromagnetic layer 10 has the shortest width L10 min in the z direction. It is darker than the second region R2 on the non-magnetic layer 30 side from the position where.

"Non-magnetic layer"
The non-magnetic layer 30 is in contact with, for example, the first ferromagnetic layer 10. The non-magnetic layer 30 is on the first ferromagnetic layer 10. The non-magnetic layer 30 is located between the first ferromagnetic layer 10 and the second ferromagnetic layer 20.

The non-magnetic layer 30 is made of, for example, a non-magnetic insulator, a semiconductor or a metal. The non-magnetic insulator is, for example, Al ₂ O ₃ , SiO ₂ , MgO, MgAl ₂ O ₄ , and a material in which some of these Al, Si, and Mg are replaced with Zn, Be, and the like. These materials have a large bandgap and excellent insulation. When the non-magnetic layer 30 is made of a non-magnetic insulator, the non-magnetic layer 30 is a tunnel barrier layer. The non-magnetic metal is, for example, Cu, Au, Ag or the like. Non-magnetic semiconductors are, for example, Si, Ge, CuInSe ₂ , CuGaSe ₂ , Cu (In, Ga) Se _{2 and the} like.

The milling rate of the non-magnetic layer 30 is slower than, for example, the milling rate of the first ferromagnetic layer 10. The milling rate is the milling rate for dry etching. For dry etching, for example, ion beam etching is used. Noble gas elements such as Ar, Kr, and Xe, or ions thereof, can be used for ion beam etching, which is accelerated by a voltage of several hundred to several kV, and for milling. When the non-magnetic layer 30 is an oxide, the milling rate is often slower than that of the first ferromagnetic layer 10 which is a metal.

The thickness of the non-magnetic layer 30 is preferably 20 Å or more, more preferably 30 Å or more. When the thickness of the non-magnetic layer 30 is large, the resistance area product (RA) of the domain wall moving element 100 becomes large. The resistance area product (RA) of the domain wall moving element 100 ^{is preferably 1 × 10 4} Ω μm ² or more, and more preferably 1 × 10 ⁵ Ω μm ² or more. The resistance area product (RA) of the domain wall moving element 100 is the product of the element resistance of one domain wall moving element 100 and the element cross-sectional area of the domain wall moving element 100 (the area of the cut surface obtained by cutting the non-magnetic layer 30 in the xy plane). expressed.

Further, when the non-magnetic layer 30 is thick and the milling rate is different from that of other layers during slimming, impurities tend to reattach to the side wall of the non-magnetic layer 30. By controlling the relationship between the width L30 in the y direction of the non-magnetic layer 30 and the shortest width L10 min in the y direction of the first ferromagnetic layer 10, even if the thickness of the non-magnetic layer 30 is thick, the side wall of the non-magnetic layer 30 can be reached. Reattachment of impurities can be suppressed.

"Second ferromagnetic layer"
The second ferromagnetic layer 20 is on the non-magnetic layer 30. The second ferromagnetic layer 20 has a magnetization M ₂₀ oriented in one direction. Magnetization _{M 20} of the second ferromagnetic layer 20, the magnetization _M 13A of the magnetic domain wall moving region 13 when a predetermined external force is _applied, it _is difficult to magnetization reversal than _{M 13B.} The predetermined external force is, for example, an external force applied to the magnetization by an external magnetic field or an external force applied to the magnetization by a spin polarization current. The second ferromagnetic layer 20 may be referred to as a magnetization fixed layer or a magnetization reference layer.

The resistance value of the domain wall moving element 100 changes depending on the difference in the relative angle between the magnetization of the second ferromagnetic layer 20 and the magnetizations M _13A and M _{13B of the domain wall moving region 13.} Magnetization _{M 13A} of the first magnetic domain 13A is, for example, the same direction as the magnetization _{M 20} of the second ferromagnetic layer 20 (parallel), the magnetization _{M 13B} of the second magnetic domain 13B, for example magnetization M of the second ferromagnetic layer 20 _It is in the opposite direction (antiparallel) to 20. When the area of the first magnetic domain 13A in the portion overlapping with the second ferromagnetic layer 20 in the plan view from the z direction becomes large, the resistance value of the domain wall moving element 100 becomes low. On the contrary, when the area of the second magnetic domain 13B in the portion overlapping with the second ferromagnetic layer 20 in the plan view from the z direction becomes large, the resistance value of the domain wall moving element 100 becomes high.

The second ferromagnetic layer 20 contains a ferromagnet. The second ferromagnetic layer 20 contains, for example, a material that easily obtains a coherent tunneling effect with the first ferromagnetic layer 10. The second ferromagnetic layer 20 is, for example, a metal selected from the group consisting of Cr, Mn, Co, Fe and Ni, an alloy containing one or more of these metals, and at least these metals and B, C, and N. Includes alloys and the like containing one or more elements. The second ferromagnetic layer 20 is, for example, Co—Fe, Co—Fe—B, Ni—Fe.

The second ferromagnetic layer 20 may be, for example, a Whistler alloy. The Whisler alloy is a half metal and has a high spin polarizability. The Whisler alloy is an _{intermetallic compound with a chemical composition of XYZ or X 2} YZ, where X is a transition metal element or noble metal element of the Co, Fe, Ni or Cu group on the periodic table, and Y is Mn, V. , Cr or a transition metal of Group Ti or an elemental species of X, and Z is a typical element of Group III to Group V. Examples of the _{Whisler alloy include Co 2} FeSi, Co ₂ FeGe, Co ₂ FeGa, Co ₂ MnSi, Co ₂ Mn _1-a Fe _a Al _b Si _1-b , and Co ₂ FeGe _1-c Ga _c .

The thickness of the second ferromagnetic layer 20 is preferably 1.5 nm or less, preferably 1.0 nm or less, when the easy axis of magnetization of the second ferromagnetic layer 20 is in the z direction (perpendicular magnetization film). Is more preferable. When the film thickness of the second ferromagnetic layer 20 is reduced, the second ferromagnetic layer 20 has a perpendicular magnetic anisotropy (interfacial vertical magnetism) at the interface between the second ferromagnetic layer 20 and another layer (non-magnetic layer 30). Anisotropy) is added, and the magnetism of the second ferromagnetic layer 20 tends to be oriented in the z direction.

When the easy axis of magnetization of the second ferromagnet layer 20 is in the z direction (a vertical magnetization film is used), the second ferromagnet layer 20 is a ferromagnet selected from the group consisting of Co, Fe, and Ni, and Pt. It is preferable to use a laminated body with a non-magnetic material selected from the group consisting of Pd, Ru, and Rh, and an intermediate layer selected from the group consisting of Ir and Ru may be inserted at any position of the laminated body. More preferred. Vertical magnetic anisotropy can be added by laminating a ferromagnetic material and a non-magnetic material, and by inserting an intermediate layer, the magnetization of the second ferromagnetic layer 20 can be easily oriented in the z direction.

An antiferromagnetic layer may be provided on the surface of the second ferromagnetic layer 20 opposite to the non-magnetic layer 30 via a spacer layer. The second ferromagnetic layer 20, the spacer layer, and the antiferromagnetic layer have a synthetic antiferromagnetic structure (SAF structure). The synthetic antiferromagnetic structure consists of two magnetic layers sandwiching the non-magnetic layer. Since the second ferromagnetic layer 20 and the antiferromagnetic layer are antiferromagnetic coupled, the coercive force of the second ferromagnetic layer 20 becomes larger than that in the case where the antiferromagnetic layer is not provided. The antiferromagnetic layer is, for example, IrMn, PtMn, or the like. The spacer layer contains, for example, at least one selected from the group consisting of Ru, Ir, Rh.

The base layer 40 is on the opposite side of the first ferromagnetic layer 10 from the non-magnetic layer 30. The base layer 40 may be present only at a position overlapping with the domain wall moving region 13 in the z direction.

The base layer 40 is made of a non-magnetic material. The base layer 40 defines, for example, the crystal structure of the first ferromagnetic layer 10. The crystal structure of the base layer 40 enhances the crystallinity of the first ferromagnetic layer 10 and enhances the orientation of the magnetization of the first ferromagnetic layer 10. The crystal structure of the base layer 40 may be, for example, amorphous, (001) oriented NaCl structure, (002) oriented perovskite structure represented by the composition formula of _{ABO 3, (001) oriented rectangular structure or cubic structure.} be.

The base layer 40 is a conductor or an insulator. The base layer 40 is preferably a conductor. When the base layer 40 is a conductor, the thickness of the base layer 40 is preferably thinner than the thickness of the first ferromagnetic layer 10. The base layer 40 contains, for example, Ta, Ru, Pt, Ir, Rh, W, Pd, Cu, Au, and Cu. The base layer 40 is, for example, a Ta layer, a Pt layer, or a laminate of a Ta layer and a Pt layer.

The underlayer 40 has a slower milling rate than, for example, the first ferromagnetic layer 10. Further, the underlayer 40 has a slower milling rate than, for example, the first conductive portion 51 and the second conductive portion 52. For example, the base layer 40 contains one or more elements selected from Al, Cr, Mg, Ta, Ti, and W, and the first ferromagnetic layer 10 is selected from Co, Fe, Ni, Pt, Pd, Ir, and Rh. The above relationship is satisfied when the first conductive portion 51 and the second conductive portion 52 are alloys or laminates containing one or more elements selected from Au, Cu, and Ru. Specifically, for example, when the underlayer is Ta or a laminated film of Ta and Pt, the first ferromagnetic layer 10 is a laminated film of Co and Pt, and the first conductive portion 51 and the second conductive portion 52 are Au. Can be given.

The thickness of the base layer 40 is, for example, substantially constant in the xy plane. The average thickness of the base layer 40 is, for example, 50 Å or less. The average thickness is an average value of the thickness of the base layer 40 measured at each position in the x direction in which the base layer 40 is divided into 10 at equal intervals in the x direction.

"1st conductive part and 2nd ferromagnetic part"
The first conductive portion 51 and the second conductive portion 52 are electrically connected to the first ferromagnetic layer 10. The first conductive portion 51 and the second conductive portion 52 are connected via, for example, the base layer 40 as shown in FIG. The first conductive portion 51 and the second conductive portion 52 may be directly connected to the first ferromagnetic layer 10. The first conductive portion 51 is connected to, for example, the first end portion of the first ferromagnetic layer 10, and the second conductive portion 52 is connected to, for example, the second end portion of the first ferromagnetic layer 10. The first conductive portion 51 and the second conductive portion 52 are, for example, connection portions between the wiring W and the first ferromagnetic layer 10.

The first conductive portion 51 and the second conductive portion 52 are columnar bodies. The first conductive portion 51 and the second conductive portion 52 shown in FIG. 4 have a rectangular shape in a plan view from the z direction. The shapes of the first conductive portion 51 and the second conductive portion 52 in a plan view from the z direction may be circular, elliptical, or amorphous. The width of the first conductive portion 51 and the second conductive portion 52 in the y direction is wider than, for example, the width of the first ferromagnetic layer 10 and the non-magnetic layer 30 in the y direction. The upper surfaces of the first conductive portion 51 and the second conductive portion 52 are etched, for example, and are recessed with respect to the xy plane.

The first conductive portion 51 and the second conductive portion 52 are made of a conductive material. The first conductive portion 51 and the second conductive portion 52 include, for example, a magnetic material. The first conductive portion 51 and the second conductive portion 52 are, for example, a metal selected from the group consisting of Cr, Mn, Co, Fe and Ni, an alloy containing one or more of these metals, these metals and B. , C, and alloys containing at least one element of N. The first conductive portion 51 and the second conductive portion 52 are, for example, Co—Fe, Co—Fe—B, Ni—Fe, or the like. Further, when the first conductive portion 51 and the second conductive portion 52 have the easy axis of magnetization in the z direction (to form a vertical magnetization film), the first conductive portion 51 and the second conductive portion 52 have Co, Fe. , A laminate of a ferromagnetic material selected from the group consisting of Ni and a non-magnetic material selected from the group consisting of Pt, Pd, Ru, and Rh is preferable. Further, the first conductive portion 51 and the second conductive portion 52 may have a synthetic antiferromagnetic structure (SAF structure). The synthetic antiferromagnetic structure consists of two magnetic layers sandwiching the non-magnetic layer. The magnetization of each of the two magnetic layers is fixed, and the directions of the fixed magnetization are opposite.

When the first conductive portion 51 contains a magnetic material, the magnetization M ₅₁ of the first conductive portion 51 is oriented in one direction. The magnetization M ₅₁ is oriented in the + z direction, for example. The first conductive portion 51 fixes the magnetization M ₁₁ in the magnetization fixing region 11. The magnetization _{M 11} of the magnetization _{M 51} and the magnetization fixed region 11 of the first conductive portion 51, for example, oriented in the same direction.

When the second conductive portion 52 contains a magnetic material, the magnetization M ₅₂ of the second conductive portion 52 is oriented in a direction different from _{the magnetization M 51 of} the first conductive portion 51. The magnetization M ₅₂ is oriented in the −z direction, for example. In this case, the second conductive part 52, the magnetization _{M 12} of the magnetization fixed region 12 is fixed, the magnetization _{M 12} of the magnetization _{M 52} and the magnetization fixed region 12 of the second conductive portion 52, for example, be oriented in the same direction ..

The direction of magnetization of each layer of the domain wall moving element 100 can be confirmed, for example, by measuring the magnetization curve. The magnetization curve can be measured using, for example, MOKE (Magneto Optical Kerr Effect). The measurement by MOKE is a measurement method performed by incident linearly polarized light on an object to be measured and using a magneto-optical effect (magnetic Kerr effect) in which rotation in the polarization direction occurs.

Next, a method of manufacturing the magnetic recording array 200 will be described. The magnetic recording array 200 is formed by a laminating step of each layer and a processing step of processing a part of each layer into a predetermined shape. For the lamination of each layer, a sputtering method, a chemical vapor deposition (CVD) method, an electron beam vapor deposition method (EB vapor deposition method), an atomic laser deposit method, or the like can be used. Processing of each layer can be performed using photolithography or the like.

First, impurities are doped at a predetermined position on the substrate Sub to form a source region S and a drain region D. Next, a gate insulating film GI and a gate electrode G are formed between the source region S and the drain region D. The source region S, the drain region D, the gate insulating film GI, and the gate electrode G form the transistor Tr.

Next, the insulating layer In is formed so as to cover the transistor Tr. Further, the wiring W is formed by forming an opening in the insulating layer In and filling the opening with a conductor. The first wiring Wp and the second wiring Cm are formed by laminating the insulating layer In to a predetermined thickness, forming a groove in the insulating layer In, and filling the groove with a conductor.

In the first conductive portion 51 and the second conductive portion 52, for example, a ferromagnetic layer is laminated on one surface of the insulating layer In and the wiring W, and the portions other than the portions that become the first conductive portion 51 and the second conductive portion 52 are removed. It can be formed by. The removed portion is filled with, for example, the insulating layer In.

Next, the base layer 40, the first ferromagnetic layer 10, and the non-magnetic layer 30 are laminated in this order on the first conductive portion 51, the second conductive portion 52, and the insulating layer In. Then, a resist is formed on a part of the non-magnetic layer 30. Next, the base layer 40, the first ferromagnetic layer 10, and the non-magnetic layer 30 are processed by performing dry etching from the z direction via the resist. The yz cross-sectional shape of the laminated body after processing is rectangular or trapezoidal.

Next, an ion beam is irradiated from an oblique direction aiming at the first ferromagnetic layer 10 of the laminated body. The first ferromagnetic layer 10 is recessed toward the center of the laminated body in the y direction by irradiation with an ion beam. After that, the second ferromagnetic layer 20 is laminated at a position overlapping with the first ferromagnetic layer 10.

Finally, the irradiation angle of the ion beam with respect to the xy plane is made smaller, and the ion beam is irradiated from the lateral direction of the laminate to slimm the entire laminate. The laminate is miniaturized by slimming. Finally, the domain wall moving element 100 is obtained by filling the periphery of the laminated body with the insulating layer In.

In the domain wall moving element 100 according to the first embodiment, impurities are unlikely to reattach to the side surface of the non-magnetic layer 30 during slimming. The reason for this will be described with reference to FIG. FIG. 7 is a schematic diagram for explaining slimming when the domain wall moving element 100 according to the first embodiment is manufactured.

As described above, at the time of slimming, the ion beam IB is irradiated from the y direction to the laminated body composed of the base layer 40, the first ferromagnetic layer 10, the non-magnetic layer 30 and the second ferromagnetic layer 20. It is difficult to irradiate the ion beam IB in parallel with the y direction, and the ion beam IB is irradiated from a direction slightly inclined in the z direction with respect to the xy plane. For example, when the first ferromagnetic layer 10 is irradiated with an ion beam IB, the metal particles contained in the first ferromagnetic layer 10 are scattered as particles pt.

In the domain wall moving element 100 according to the first embodiment, since the shortest width L10 min in the y direction of the first ferromagnetic layer 10 is shorter than the width L30 in the y direction of the non-magnetic layer 30, the non-magnetic layer 30 serves as a cover and the particles pt. Is suppressed from reattaching to the side wall of the non-magnetic layer 30.

Further, when the first ferromagnetic layer 10 has the second inclined surface s2, the second inclined surface s2 overhangs the first inclined surface s1, so that the particle pt reaches the side wall of the non-magnetic layer 30. Can be further suppressed. Further, when the position where the width of the first ferromagnetic layer 10 in the y direction is the shortest is on the non-magnetic layer 30 side from the center of the first ferromagnetic layer 10 in the z direction, the portion close to the non-magnetic layer 30 is inside. It will be dented toward the side, and it is possible to further suppress the particle pt from reaching the side wall of the non-magnetic layer 30.

Further, when the milling rate of the non-magnetic layer 30 and the base layer 40 is slower than that of the first ferromagnetic layer 10, the side surface of the first ferromagnetic layer 10 with respect to the side surface of the non-magnetic layer 30 and the base layer 40 as the slimming progresses. Go inside. Therefore, the non-magnetic layer 30 serves as a cover, and the reattachment of the particle pt to the side wall of the non-magnetic layer 30 is further suppressed. Further, when the milling rate of the base layer 40 is made slower than the milling rate of the first conductive portion 51 and the second conductive portion 52, the base layer 40 becomes a cover, and the particles pt scattered from the first conductive portion 51 or the second conductive portion 52 are generated. It is possible to further suppress reaching the side wall of the non-magnetic layer 30.

Further, when the first ferromagnetic layer 10 contains an element constituting the base layer 40, the amount of particles pt scattered from the first ferromagnetic layer 10 can be reduced. Further, by making the abundance ratio of the elements constituting the base layer 40 in the first region R1 higher than that in the second region R2, the particle pt from the first region R1 can easily secure a path for the particle pt to reach the non-magnetic layer 30. Occurrence can be suppressed.

Impurities formed by the adhesion of particles lower the MR ratio of the domain wall moving element 100, and in some cases, short-circuit the first ferromagnetic layer 10 and the second ferromagnetic layer 20. The domain wall moving element 100 according to the first embodiment is highly reliable because it can reduce the adhesion of impurities to the side wall of the non-magnetic layer 30.

Although an example of the magnetic recording array 200 and the domain wall moving element 100 according to the first embodiment has been described in detail above, the magnetic recording array 200 and the domain wall moving element 100 according to the first embodiment are within the scope of the gist of the present invention. , Various modifications and changes are possible.

(First modification)
FIG. 8 is a cross-sectional view taken along the line yz at the center of the domain wall moving element 101 according to the first modification in the x direction. The domain wall moving element 101 is different from the domain wall moving element 100 in the shape of the side surface of the first ferromagnetic layer 10. The same components as those of the domain wall moving element 100 in the domain wall moving element 101 are designated by the same reference numerals, and the description thereof will be omitted.

The side surface of the first ferromagnetic layer 10 in the y direction shown in FIG. 8 is an inclined surface s3 inclined in the y direction with respect to the z direction. The inclined surface s3 is an inclined surface that is inclined so as to be away from the center in the y direction of the first ferromagnetic layer 10 with respect to the upper end of the side surface of the first ferromagnetic layer 10 on the non-magnetic layer 30 side.

The width of the first surface 10a shown in FIG. 8 in the y direction is shorter than the width L30 of the non-magnetic layer 30 in the y direction. The width of the first ferromagnetic layer 10 shown in FIG. 8 in the y direction increases from the first surface 10a to the second surface 10b. The width of the first ferromagnetic layer 10 shown in FIG. 8 in the y direction is the shortest on the first surface 10a and the longest on the second surface 10b.

In the domain wall moving element 101 according to the first modification, a part of the side surface of the first ferromagnetic layer 10 in the y direction is inside the non-magnetic layer 30. Therefore, the non-magnetic layer 30 becomes an eave, and the particles pt scattered from the first ferromagnetic layer 10 can be prevented from reattaching to the side wall of the non-magnetic layer 30.

(Second modification)
FIG. 9 is a cross-sectional view taken along the line yz at the center of the domain wall moving element 102 according to the second modification in the x direction. The domain wall moving element 102 is different from the domain wall moving element 100 in the shape of the side surface of the first ferromagnetic layer 10. The same components as those of the domain wall moving element 100 in the domain wall moving element 102 are designated by the same reference numerals, and the description thereof will be omitted.

The domain wall moving element 102 according to the second modification is the same as the domain wall moving element 100 in that the width of the first ferromagnetic layer 10 in the y direction is the longest on the second surface 10b, but is the same as that of the second surface 10b in the y direction. The difference is that the width is shorter than the width L30 in the y direction of the non-magnetic layer 30. In the domain wall moving element 102 according to the second modification, for example, the longest width L10max in the y direction of the first ferromagnetic layer 10 is shorter than the width L30 in the y direction of the non-magnetic layer 30.

In the domain wall moving element 102 according to the second modification, the side surface of the first ferromagnetic layer 10 in the y direction is inside the non-magnetic layer 30. Therefore, the non-magnetic layer 30 becomes an eave, and the particles pt scattered from the first ferromagnetic layer 10 can be prevented from reattaching to the side wall of the non-magnetic layer 30.

(Third modification example)
FIG. 10 is a cross-sectional view taken along the line yz at the center of the domain wall moving element 103 according to the third modification in the x direction. The domain wall moving element 103 is different from the domain wall moving element 100 in that the metal layer 60 is provided on the side surface of the second ferromagnetic layer 20. The same components as those of the domain wall moving element 100 in the domain wall moving element 103 are designated by the same reference numerals, and the description thereof will be omitted.

The metal layer 60 is, for example, on the side of the second ferromagnetic layer 20 in the y direction. The metal layer 60 is in contact with, for example, the side surface of the second ferromagnetic layer 20 in the y direction. There may be another layer between the second ferromagnetic layer 20 and the metal layer 60. Another layer is, for example, an oxide film.

The metal layer 60 is not continuous with the second ferromagnetic layer 20. Not continuous means that the interface can be confirmed by a transmission electron microscope. The metal layer 60 is different from the second ferromagnetic layer 20. Different from the second ferromagnetic layer 20 means that the material or composition is different. The metal layer 60 may be a non-magnetic material or a magnetic material.

The domain wall moving element 103 according to the third modification has the same effect as the domain wall moving element 100 according to the first embodiment. Further, the metal layer 60 projects outward from the first ferromagnetic layer 10, so that the heat dissipation of the domain wall moving element 103 is improved.

"Second embodiment"
FIG. 11 is a cross-sectional view of the domain wall moving element 110 according to the second embodiment cut in the xz plane passing through the center of the first ferromagnetic layer 70 in the y direction. FIG. 12 is a cross-sectional view taken along the yz plane passing through the center of the domain wall moving element 110 in the x direction. The plan view of the domain wall moving element 110 according to the second embodiment from the z direction is the same as that of FIG.

The domain wall moving element 110 has, for example, a first ferromagnetic layer 70, a second ferromagnetic layer 80, a non-magnetic layer 30, an underlayer 40, a first conductive portion 51, and a second conductive portion 52. In the domain wall moving element 110, the same configuration as in the first embodiment is designated by the same reference numerals. The first ferromagnetic layer 70 is on the substrate Sub side with respect to the second ferromagnetic layer 0.

When writing data to the domain wall moving element 110, a writing current is passed through the second ferromagnetic layer 80 between the first conductive portion 51 and the second conductive portion 52. When reading data from the domain wall moving element 100, a reading current is passed between the first conductive portion 51 or the second conductive portion 52 and the first ferromagnetic layer 70.

The first ferromagnetic layer 70 has a magnetization M ₇₀ oriented in one direction. The first ferromagnetic layer 70 is a magnetization fixed layer and a magnetization reference layer. The first ferromagnetic layer 70 is functionally equivalent to the second ferromagnetic layer 20 according to the first embodiment. The domain wall moving element 110 has a bottom pin structure in which the magnetization fixing layer is on the substrate Sub side. As the first ferromagnetic layer 70, the same material as the second ferromagnetic layer 20 can be used. The first ferromagnetic layer 70 may contain elements constituting the base layer 40.

A write current is energized in the second ferromagnetic layer 80. The second ferromagnetic layer 80 is functionally the same as the first ferromagnetic layer 10 according to the first embodiment. As the second ferromagnetic layer 80, the same material as the first ferromagnetic layer 10 can be used.

The second ferromagnetic layer 80 is a layer capable of magnetically recording information by changing the internal magnetic state. The second ferromagnetic layer 80 may be referred to as a magnetic recording layer or a domain wall moving layer. The second ferromagnetic layer 80 has a magnetization fixing region 81, 82 and a domain wall moving region 83. The magnetization M ₈₁ in the magnetization fixing region _{81 and the magnetization M 82 in the} magnetization fixing region 82 are oriented in opposite directions. The domain wall moving region 83 has a first magnetic domain 83A and a second magnetic domain 83B. The boundary between the first magnetic domain 83A and the second magnetic domain 83B is the domain wall DW. _{The magnetization M 83A} and the magnetization M _84A are oriented in opposite directions with the domain wall DW interposed therebetween.

As shown in FIG. 12, the shortest width L70min in the y direction of the first ferromagnetic layer 70 is shorter than the width L30 in the y direction of the non-magnetic layer 30. The width of the first ferromagnetic layer 70 in the y direction differs depending on the position in the z direction. For example, the first surface 70a and the second surface 70b of the first ferromagnetic layer 70 have different widths in the y direction. The width of the first ferromagnetic layer 70 in the y direction narrows from the first surface 10a toward the second surface 10b, reaches the shortest width L70min, and then widens. The position where the shortest width is L70 min is, for example, the non-magnetic layer 30 side from the center of the first ferromagnetic layer 10 in the z direction. The longest width L70max in the y direction of the first ferromagnetic layer 70 is, for example, longer than the width L30 in the y direction of the non-magnetic layer 30.

The side surface of the first ferromagnetic layer 70 in the y direction is inclined in the y direction with respect to the z direction, for example. The side surface of the first ferromagnetic layer 70 in the y direction can be divided into a first inclined surface s1 and a second inclined surface s2. The side surface of the first ferromagnetic layer 70 in the y direction is recessed with respect to, for example, a virtual surface lowered in the z direction from the end portion of the non-magnetic layer 30 in the y direction.

The milling rate of the non-magnetic layer 30 is slower than, for example, the milling rate of the first ferromagnetic layer 70. The underlayer 40 has a slower milling rate than, for example, the first ferromagnetic layer 70.

In the domain wall moving element 110 according to the second embodiment, since the shortest width L70 min in the y direction of the first ferromagnetic layer 70 is shorter than the width L30 in the y direction of the non-magnetic layer 30, the non-magnetic layer 30 serves as a cover and the particles pt. Is suppressed from reattaching to the side wall of the non-magnetic layer 30. The domain wall moving element 110 according to the second embodiment has the same effect as the domain wall moving element 100 according to the first embodiment. Further, for the domain wall moving element 110 according to the second embodiment, a modification similar to that of the first embodiment can be selected.

The preferred embodiments of the present invention have been described in detail above. The characteristic configurations in each embodiment and modification may be combined.

10, 70 First ferromagnetic layer 10a, 70a First surface 10b, 70b Second surface 20, 80 Second ferromagnetic layer 30 Non-magnetic layer 40 Underlayer 51 First conductive section 52 Second conductive section 60 Metal layer 100, 101, 102, 103, 110 Magnetic wall moving element 200 Magnetic recording array L10max Longest width L10min Shortest width L30 Width R1 First area R2 Second area s1 First inclined surface s2 Second inclined surface s3 Inclined surface

Claims (14)

The first ferromagnetic layer, the non-magnetic layer, and the second ferromagnetic layer are laminated in this order from the side closest to the substrate.
In a cut surface cut along a second direction orthogonal to the first direction in which the first ferromagnetic layer extends in a plan view from the stacking direction.
A domain wall moving element in which the shortest width of the first ferromagnetic layer in the second direction is shorter than the width of the non-magnetic layer in the second direction. The domain wall moving element according to claim 1, wherein the side surface of the first ferromagnetic layer is inclined with respect to the stacking direction in the cut surface along the stacking direction and the second direction. In the cut surface along the stacking direction and the second direction, the side surface of the first ferromagnetic layer has a first inclined surface and a second inclined surface.
The first inclined surface is inclined from the lower end of the first ferromagnetic layer on the side close to the substrate toward the center of the first ferromagnetic layer in the second direction.
The magnetic domain wall moving element according to claim 2, wherein the second inclined surface is inclined from the upper end of the first ferromagnetic layer on the side far from the substrate toward the center of the first ferromagnetic layer in the second direction. The width of the first surface of the first ferromagnetic layer on the non-magnetic layer side in the second direction is shorter than the width of the non-magnetic layer in the second direction, according to any one of claims 1 to 3. The described domain wall moving element. The position where the width of the first ferromagnetic layer in the second direction is the shortest is any one of claims 1 to 4, which is on the non-magnetic layer side from the center of the first ferromagnetic layer in the stacking direction. The domain wall moving element described in the section. The domain wall moving element according to any one of claims 1 to 5, wherein the longest width of the first ferromagnetic layer in the second direction is shorter than the width of the non-magnetic layer in the second direction. Any one of claims 1 to 5, wherein the width of the second surface of the first ferromagnetic layer far from the non-magnetic layer in the second direction is longer than the width of the non-magnetic layer in the second direction. The domain wall moving element described in the section. The domain wall moving element according to any one of claims 1 to 7, wherein the thickness of the non-magnetic layer is 30 Å or more. The domain wall moving element according to any one of claims 1 to 8, wherein the milling rate of the non-magnetic layer is slower than the milling rate of the first ferromagnetic layer. An underlayer is further provided on the opposite side of the first ferromagnetic layer to the non-magnetic layer.
The magnetic domain wall moving element according to any one of claims 1 to 9, wherein the underlying layer has a slower milling rate than the first ferromagnetic layer. The first ferromagnetic layer contains elements constituting the underlayer and contains elements.
The abundance ratio of the element is such that the first region on the base layer side from the position where the width of the first ferromagnetic layer in the second direction is the shortest in the stacking direction is the first ferromagnet in the stacking direction. The magnetic wall moving element according to claim 10, which is darker than the second region on the non-magnetic layer side from the position where the width of the layer in the second direction is the shortest. It has a first conductive portion and a second conductive portion that sandwich the non-magnetic layer in the first direction and are electrically connected to the first ferromagnetic layer via the base layer.
The width of each of the first conductive portion and the second conductive portion in the second direction is wider than the width of the first ferromagnetic layer in the second direction.
The domain wall moving element according to claim 10, wherein the milling rate of the base layer is slower than the milling rate of the first conductive portion and the second conductive portion. The magnetic wall moving element according to any one of claims 1 to 12, further comprising a metal layer different from the second ferromagnetic layer on the side of the second ferromagnetic layer in the second direction. A magnetic recording array having a plurality of domain wall moving elements according to any one of claims 1 to 13.

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