JPH0478091A - Bloch line memory element - Google Patents

Abstract

PURPOSE:To enlarge the common margins of transfer margins at the both edge parts of a group for fitting a stripe magnetic domain, and to enable the revolutionary transfer corresponding to a Bloch line of the same transfer condition by reducing the difference of the shapes of the both edge parts of the group, and reducing the difference of the transfer margins at the both edge parts. CONSTITUTION:The shapes of the edge parts of the mask patterns 12 and 13 of the group are corrected so that the shape of the edge part of the group carved on a strong magnetic substance film can be the same with that of the other edge part in order to fit the stripe magnetic domain. That is, when the mask patterns 12 and 13 are shaped like a recessed shape at the edge parts in a length direction 21 which are shaped like a triangle, the inclination of the edge parts to the triangular shape is suppressed by a phosphate etching. And also, when the mask patterns 12 and 13 are shaped like a recessed shape at the edge parts in a length direction 22 which are shaped like a square, the edge parts are close to the triangular shapes, and the difference of the shapes of the both edge parts of the group can be reduced. Thus, the common margins of the transfer margins corresponding to the Bloch line at the two edge parts of the stripe magnetic domain can be enlarged, and the revolutionary transfer on the same transfer condition can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a solid-state magnetic memory, and particularly to a Bloch line memory element suitable for realizing a large-capacity file memory.

[Conventional technology 1] In a Bloch line memory element, the presence or absence of Bloch line pairs present in the domain walls of striped magnetic domains arranged in parallel in a magnetic garnet film with the axis of easy magnetization perpendicular to the film surface is used to determine the presence or absence of Bloch line pairs. Information is stored in association with tr 1 uLL 01+. Regarding the Bloch line memory element, the basic structure is described in Japanese Patent Laid-Open No. 101092/1983. Regarding the arrangement of striped magnetic domains, for example, I.E.E., transaction on
Magnetic Sox, M.N.G.22, Number 5 (
1986) pp. 784-789 (IEEE
analysis on magnetics,
Vol+MAG-22,~o,5. (1986) pp7
84-pp789). This will be explained with reference to FIG.

FIG. 5 shows a perspective view of a portion of striped magnetic domains that constitute the storage section of the Bloch line memory.

As shown in the figure, grooves called groups 200 are formed in the magnetic garnet film to have the same depth as the film thickness. Then, the stripe magnetic domains 1 are fixed around the group 200 due to the magnetostatic interaction between the group 200 and the stripe magnetic domains 1. By forming a large number of these groups 200 in parallel, striped magnetic domains can be arranged. This group creates a mask pattern of elongated rectangular groups formed from a 5in2 film on a magnetic garnet film, applies distortion to the group pattern part by ion implantation, and selectively etches the part with hot phosphoric acid. It is formed by

In addition, as described in Japanese Patent Application Laid-Open No. 63-225989, in order to improve the transfer characteristics of Bloch line pairs, the longitudinal direction of the group pattern is aligned with the crystal orientation of the magnetic garnet film [1■2■], [■] and [1■2■], [■].

[■2■], [■1 and [■2■], [■11, [2
11] and [21, 1].

[Problems to be Solved by the Invention] In the above prior art, when the mask pattern of the group is made into a rectangular shape as shown in FIG. 6, the end shape of the group formed by repeating ion implantation and phosphoric acid etching is are different at both ends as shown in FIG. This is a magnetic garnet film (7) (100) plane, (010)
This is because the etching speed of the plane and (001) plane is faster than other planes, and the longitudinal direction parallel to the crystal orientations [■■2], [1■1], and [211] of the magnetic garnet film. The ends of 21 are triangular, [1■2■], [■]
, [■2■], [■11, and the ends in the longitudinal direction 22 parallel to the [211] directions have a rectangular shape. When the end shapes of the groups are different in this way, the magnetostatic force acting between the group end and the striped magnetic domain end becomes different at both ends, and the movement of the domain wall also becomes different at both ends. Since the transfer of the Bloch line pair is greatly influenced by the movement of the domain wall, the transfer margin of the Bloch line pair differs at both ends of the striped magnetic domain, and there is no common margin. Therefore, 8 round transfers do not occur under the same transfer conditions.

An object of the present invention is to widen the common transfer margin of the Bloch line pair at the two ends of a striped magnetic domain, and to enable circular transfer under the same transfer conditions.

[Means for Solving the Problems] The second object is to form a magnetic garnet film whose longitudinal direction is in a magnetic garnet film formed on a substrate surface so that the (1, 11,) plane is the film surface. Crystal orientation [1■2■], [■]
and [■■2], [1■1co and [:1.21-],
[2] In a Bloch line memory element in which the information carrier is a Bloch line pair existing in the domain wall of a striped magnetic domain arranged parallel to either [1,1] or [21,1], the striped magnetic domain is fixed. The end shape of the mask pattern of the group to be dug in the magnetic garnet film is made concave at the end in the direction [2111], or rectangular in the crystal orientation [11] of the magnetic garnet film. Or, the crystal orientation of the magnetic garnet film [1■2■], [■co,
[■2■], [■11, [2] Rectangular shape at the end in the 1 direction, [11,2], [■2■], [■1],
This is achieved by creating a concave shape at the end in the [211] direction.

[Effect 1 When the end shape of the mask pattern of a group is the same at both ends, the end shape of the group formed by repeating ion implantation and phosphoric acid etching will be the same at both ends as shown in FIG. It varies by department. This is because the etching rate of the magnetic garnet film differs depending on the crystal orientation of the film.
[■], [■2■], [■LL The end in the longitudinal direction 21 parallel to the [211] direction is triangular, [1■2■],
At the ends of the longitudinal direction 22 parallel to the [■], [■2■], [■1co], and [211] directions, the shape approaches a square.

Therefore, if the mask pattern is made concave at the ends in the longitudinal direction 21 where the ends become triangular, it is possible to prevent the ends from becoming triangular due to phosphoric acid etching. In addition, the longitudinal direction 2 where the end part is square shaped
If the mask pattern is made into a convex shape at the end of 2, the end becomes close to a triangular shape. This makes it possible to reduce the difference in shape between both ends of the group.

[Example] Hereinafter, an example of the present invention will be described with reference to FIGS. 1, 2, and 3.

FIG. 2 is a diagram showing the functional parts of a Bloch line memory element. The striped magnetic domains 1 exist in a 5 μm thick CaGe-based magnetic garnet film grown in a liquid phase on a 0.4 mm thick gadolinium gallium garnet substrate, and are fixed around the striped magnetic domain fixing group 200.

The guide group 201 serves as a guide when stretching the stripe magnetic domain when writing and reading information. The guard group 202 prevents unnecessary magnetic domains from entering the functional section from the outside. These 200.20
1.202 Group C: A group mask pattern made of Sco02 is made on the magnetic car screw 1~ film, strain is applied to the group pattern portion by ion implantation, and the strained portion is heated with hot phosphoric acid. Formed by selective etching.

The Bloch line 7 existing in the domain wall 2 is a dummy Bloch line for keeping the Bloch line pair 8, which is an information carrier, stable. Bloch line pairs 8, which are information carriers present in the domain wall 2, are fixed by potential wells created by the magnetic pattern 6. For the magnetic pattern 6, after flattening the groups dug in the magnetic garnet film with polyimide resin, Co-
300 to 400 Pt films were deposited and formed into a desired pattern shape by photolithography.

FIG. 1 shows the shape of a mask pattern of a stripe magnetic domain fixing group. In a magnetic garnet film, the etching rate of the film differs depending on the crystal orientation, and the etching rate of the (100) plane, (010) plane, and (001) plane is higher than that of other planes. Therefore, when a group is formed by repeating ion implantation and phosphoric acid etching, the shape of the end will be the same as the crystal orientation of the magnetic garnet film [l 2
], [■], [■2■], [■1], [triangular shape at the end in the longitudinal direction 21 parallel to the 211F direction, [■■2]
, [1*1co] At the end in the longitudinal direction 22 parallel to the [211] direction, the shape approaches a square shape. Therefore, mask patterns ■2■], [■. By making the mask pattern concave at the ends in the longitudinal direction 21 where the ends become triangular, as shown in 13, it is possible to prevent the ends from becoming triangular due to phosphoric acid etching.

Furthermore, if the mask pattern is made convex at the ends in the longitudinal direction 22 where the ends are square, the ends approach a triangular shape.

As a result, the shape of the group formed by repeating ion implantation and phosphoric acid etching becomes as shown in FIG. 3, and the difference in shape between both ends becomes small. It is also possible to reduce this difference between both ends by using the mask pattern shown in FIG.

That is, by forming the end portions in the longitudinal direction 21 into a large concave shape as in the mask pattern 14, the end portions are less likely to have a triangular shape than the mask pattern shown in FIG. 2, and become closer to a quadrangular shape. Therefore, even if the ends in the longitudinal direction 22 remain square, the difference in shape between both ends becomes small. Conversely, by making the end portion in the longitudinal direction 22 a large convex shape as in the mask pattern 15, the shape of this end portion approaches the triangular shape of the end portion in the longitudinal direction 21. Therefore, even if the ends in the longitudinal direction 21 remain square, the difference in shape between both ends becomes small.

According to this embodiment, the stripe magnetic domain fixing group 20
The difference in shape between both ends of 0 becomes smaller, and the difference in transfer margin between both ends becomes smaller. As a result, the common margin for transfer at both ends is expanded, and it becomes possible to carry out circular transfer of a pair of Bloch lines under the same transfer conditions.

[Advantageous Effects of the Invention 1] According to the present invention, the difference in shape between both ends of the groove for fixing striped magnetic domains is reduced, and the difference in transfer margin between both ends is reduced. As a result, the common margin for transfer at both ends of one is expanded, and circular transfer of a pair of Bloch lines becomes possible under the same transfer conditions.

[Brief explanation of the drawing]

1 and 4 are plan views of group forming mask patterns according to embodiments of the present invention, FIG. 2 is a plan view of essential parts of a Bloch line memory device according to an embodiment of the present invention, and FIG. FIG. 5 is a perspective view showing the basic structure of a Bloch line memory element; FIG. 6 is a plan view showing the shape of a conventional group forming mask pattern; FIG. 7 is a conventional pattern. FIG. 3 is a plan view of a group shape based on a mask pattern. Explanation of symbols 1...Stripe magnetic domain, 2...Domain wall, 3...Magnetic Carnet film, 4...Nonmagnetic substrate, 5...Magnetization direction, 6
...Magnetic material pattern, 7...Bloch line, 8.
・Bloch line pair, 11 to 15...Mask pattern of group, 21.22...Longitudinal direction of group, 1
01゜102... Group shape, 200... Magnetic domain fixing group, 201... Guide group, 202...
・'f''-''' for Gara
2■ 1 mouth (kyu) (b)

Claims (1)

[Claims] 1. A ferromagnetic film formed on a substrate surface so that the (111) plane is the film surface, and a large number of Bloch line pairs are arranged in the domain walls of striped magnetic domains. In a memory element serving as an information carrier, the edges of the mask pattern of the group are etched into the ferromagnetic film to fix the striped magnetic domain so that the edge shape of the group is the same at both ends of the group. A Bloch line memory element characterized by shape correction. 2. In claim 1, the longitudinal direction is the crystal orientation of the ferromagnetic film [11■], [■■2], [1■
1], [■2■], [■11], and [2■■] Bloch line memory in which Bloch line pairs existing in the domain walls of striped magnetic domains arranged in parallel with any one of [■2■], [■11], and [2■■] serve as information carriers. In the element, the shape of the end of the group mask pattern dug into the ferromagnetic film to fix the striped magnetic domain is aligned with the crystal orientation [11
■], [1■1], and [■11] directions have a convex shape, and [■■2], [■2■], and [2■■] directions have a concave shape. Bloch line memory element. 3. In claim 1, the longitudinal direction is the crystal orientation of the ferromagnetic film [11■] and [■■2
], [1■1] and [■2■], [■11] and [2■
■] In a Bloch line memory element in which the information carrier is a Bloch line pair existing in the domain wall of a striped magnetic domain arranged parallel to one of the striped magnetic domains, a ferromagnetic film is dug in order to fix the striped magnetic domain. The end shape of the mask pattern of the group is convex at the end in the crystal orientation [11■], [1■1], [■11] direction of the ferromagnetic film, [■■2], [■2 A Bloch line memory element characterized by having a rectangular shape at the ends in the [2] and [2■■] directions. 4. In claim 1, the longitudinal direction is the crystal orientation of the ferromagnetic film [11■], [■■2], [1■
1], [■2■], [■11], and [2■■] Bloch line memory in which Bloch line pairs existing in the domain walls of striped magnetic domains arranged in parallel with any one of [■11] and [2■■] serve as information carriers. In the element, the shape of the end of the group mask pattern dug into the ferromagnetic film to fix the striped magnetic domain is aligned with the crystal orientation [11
It is characterized by having a rectangular shape at the ends in the [■■2], [■2■], and [2■■] directions, and a concave shape at the ends in the [■■2], [■2■], and [2■■] directions. Bloch line memory element. 5. The Bloch line memory device according to claim 2, wherein the ferromagnetic film is a magnetic garnet film.