JPH04155687A - Bloch line memory element - Google Patents

Abstract

PURPOSE:To realize circulation transfer of Bloch line pair under the same transfer condition by providing a second magnetic pattern outside a magnetic material pattern for deciding the bit positions of the pair, and correcting a leakage magnetic flux distribution. CONSTITUTION:Bloch line pair 6 of a carrier of information existing in a mag netic wall 10 are secured by means of magnetostatically mutual action with a magnetic field formed by magnetic material patterns 3, 3-1. A magnetic mate rial pattern 4 is a pattern for correcting a leakage magnetic field distribution at the upper and lower ends of the film pattern 3, and was formed in the same layer as the pattern 3. When the patterns 3, 4 are magnetized in the lateral direction of the pattern in the same direction, leakage magnetic field at the upper and lower ends of the pattern 3 can be corrected. Accordingly, an irregu larity in a leakage magnetic field amplitude from the pattern at the end of a stripe magnetic domain is reduced, and a circulation transfer can be performed under the same condition.

Description

[Detailed description of the invention] [Industrial application field]

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 Technique #11] In a Bloch line memory element, information is provided on the presence or absence of Bloch line pairs present in the domain walls of striped magnetic domains arranged in parallel in a ferromagnetic material whose axis of easy magnetization is perpendicular to the film surface. "1" jj Q jfi, and it is important to determine the position of the Bloch line pair. As described in Japanese Patent Application Laid-open No. 59-98384, a magnetic film pattern is periodically formed in a direction substantially perpendicular to the longitudinal direction of the striped magnetic domain, and the leakage magnetic field generated from the magnetic film pattern and the Bloch The position of the Bloch line pair was determined by using magnetostatic interaction with the line pair. [Problems to be Solved by the Invention] In the above-mentioned prior art, the non-uniformity of the in-plane component of the leakage magnetic field from the magnetic material pattern at the ends of the striped magnetic domains becomes large. Figure 3 shows the leakage magnetic field generated from the magnetic material pattern 3 in the plane of the ferromagnetic material when the strip-shaped magnetic material patterns arranged periodically in the throat of the same figure (a) are magnetized in the width direction. The distribution of the components at the ends of the striped magnetic domain 2 is shown. A to E in the figure are respectively bit positions (stable positions) of one Bloch line pair. As can be seen from the figure, the amplitude of the in-plane magnetic field is different when the Bloch line pair is transferred from bit position 1FB to C and when it is transferred from C to D. During transfer, the Bloch line pair receives a magnetostatic force from this in-plane magnetic field in the opposite direction to the transfer direction. This force is proportional to the amplitude of the in-plane magnetic field. Therefore, when transferring from B to C, it is necessary to apply a larger driving force to the Bloch line pair than when transferring from C to D. Therefore, there was a problem in that the transfer conditions were different between the two, making it impossible to perform circular transfer under the same transfer conditions. An object of the present invention is to realize circular transfer of Bloch line pairs under the same transfer conditions.

[Means to solve the problem]

The above object is a Bloch line in which information carriers are Bloch and line pairs existing in the domain walls of striped magnetic domains arranged in parallel in a ferromagnetic film whose axis of easy magnetization is perpendicular to the film surface. In the memory element, a second magnetic pattern is formed on the outside of the first magnetic pattern that defines the bit position of the Bloch line pair formed directly on the ferromagnetic film or via a spacer.
This is achieved by forming a magnetic material pattern or a pattern row to correct the non-uniform amplitude of the component in the film plane at the end of the stripe magnetic domain of the leakage magnetic field generated from the first magnetic material pattern. .

[Effect]

A second magnetic material pattern or a pattern row is formed outside the first magnetic material pattern that defines the bit position of the Bloch line pair, and a stripe magnetic domain end of the leakage magnetic field generated from the first magnetic material pattern is formed. By correcting the non-uniformity of the amplitude of the component within the film plane, the difference in the required driving force between the transfer from the stripe magnetic domain straight portion to the edge and the transfer from the edge to the straight portion becomes smaller. As a result, there is no difference in the transfer conditions between the two, and circular transfer of the Bloch line pair becomes possible under the same transfer conditions.

【Example】

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1(a) is a diagram showing a functional part of a Bloch line memory element, and FIG. 1(b) is a cross-sectional view of FIG. 1(a) taken along line segment E. The striped magnetic domain 2 has a thickness of 0.
It exists in a 5 μm thick CaGe-based magnetic garnet thin film 100 grown in a liquid phase on a 4 mm gadolinium gallium garnet substrate, and is fixed around the striped magnetic domain fixing pattern 1. The guide pattern 7 serves as a guide when stretching the striped magnetic domain during writing and reading of information.The guard pattern 8 prevents unnecessary magnetic domains from entering the functional section from the outside.These 1.7. Each pattern 8 is formed by providing grooves in the magnetic garnet film 100 itself where the striped magnetic domains 2 are present. The Bloch line 5 existing in the domain wall 10 is a dummy Bloch line that keeps the Bloch line pair 6, which is an information carrier, stable. Bloch line pairs 6, which are information carriers present in the magnet M10, are fixed by magnetostatic interaction with the magnetic field created by the magnetic material pattern 3.3-1. The magnetic patterns 3 and 3-1 are magnetic garnet films 100
After flattening the trench dug with polyimide resin 101, a Co-Pt film is deposited on it by sputtering.
0 people were deposited, and a desired pattern shape was formed by photolithography. The residual magnetic flux density of Co-pt film is 5000G
It is. Moreover, the width of the magnetic material pattern 3 is 1.25 μm,
The period in which they are lined up is 2.5 μm, and the space between them and the magnetic garnet film 100 is about 1 μm. The magnetic pattern 4 is a pattern for correcting the leakage magnetic field distribution at the upper and lower ends of the magnetic film pattern 3. The magnetic pattern 4 was formed in the same layer as the magnetic pattern 3.3-1. When the magnetic material film pattern 3 is formed under the above conditions, the magnetic material pattern 4 has, for example: (1) Film thickness: Same as magnetic material pattern 3.3-1 (2) Residual magnetic flux density: 5000G (3) Width: 5 to 10 μm (4) Distance α to magnetic pattern 3-1: 5 to 10
If the magnetic film patterns 3 and 4 are formed under the condition of .mu.m and magnetized in the width direction of the pattern and in the same direction, the leakage magnetic field distribution at the upper and lower ends of the magnetic film pattern 3 can be corrected. FIG. 2 shows the distribution of the combined leakage magnetic field generated from the two patterns at the edge of the stripe magnetic domain when the magnetic material pattern 3.4 is formed under the above conditions, and the component in the plane of the magnetic garnet film 100. FIG. There is almost no difference between the in-plane magnetic field amplitude when entering the stripe magnetic domain from the straight part to the end and the in-plane magnetic field amplitude when exiting from the end to the straight part. Therefore, there is no difference in the driving force required to transfer the Bloch line pair between the two, and there is no difference in the transferable driving magnetic field and bias magnetic field. This enables circular transfer under the same conditions. Figure 4 shows the bias magnetic field margin for transfer when entering the stripe magnetic domain from the linear part to the end and when exiting from the end to the straight part for the case (a) with the magnetic material pattern 4 and the case (b) without it. ing. As is clear from this figure, the margin difference between the two is smaller when the magnetic material pattern 4 is present than when it is absent. According to this embodiment, the non-uniformity of the leakage magnetic field amplitude from the magnetic material pattern at the ends of the striped magnetic domains is reduced, so the difference in the transfer conditions of the Bloch line pair at the ends of the striped magnetic domains is reduced, and the same transfer Circular transfer is possible under certain conditions. Effect of the invention 1 According to the present invention, the non-uniformity of the leakage magnetic field amplitude from the magnetic material pattern at the ends of the striped magnetic domains is reduced, so the difference in the transfer conditions of Bloch line pairs at the ends of the striped magnetic domains is reduced. , circular transfer under the same transfer conditions becomes possible.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a storage section of a Bloch line memory element for explaining the present invention in detail, FIG. 2 is a diagram for explaining the present invention in detail, and FIG. 3 is a diagram for explaining leakage generated from a magnetic pattern. The magnetic field distribution diagram, FIG. 4, is a diagram showing the bias magnetic field margin of Bloch line pair transfer. Explanation of symbols 1...Stripe magnetic domain fixing pattern, 2...Stripe magnetic domain, 3.3-1. ．． 4...Magnetic material pattern,
5... Bloch line, 6... Bloch line pair,
7...Guide pattern, 8...Guard pattern, 10...Domain wall, 100...Magnetic garnet, 10
1... Polyimide resin, α... Magnetic material pattern 3-
1.4 distance between

Claims (1)

[Scope of Claims] 1. Information carriers are Bloch line pairs existing in domain walls of striped magnetic domains arranged in parallel in a ferromagnetic film whose axis of easy magnetization is perpendicular to the film surface. In the Bloch line memory element, the first magnetic pattern row is located outside the first magnetic pattern row that defines the bit position of the Bloch line pair provided directly on the ferromagnetic film or via a spacer.
The ratio of the distance from the end pattern of the magnetic material pattern row to the width of the second magnetic material pattern or pattern row is 2:
A Bloch line memory element characterized in that a second magnetic material pattern or a pattern row is formed at a position with a ratio of 1 to 1:2. 2. The second magnetic material pattern or pattern row is
The leakage magnetic field generated from the magnetic material pattern is a magnetic material pattern or a pattern array that serves to reduce the non-uniformity of the amplitude of the leakage magnetic field created by the first magnetic material pattern at the edge of the striped magnetic domain. The Bloch line memory device according to range 1. 3. The Bloch line memory device according to claims 1 and 2, wherein the first magnetic material pattern and the second magnetic material pattern or pattern array are magnetized in at least the same direction. 4. A Bloch line memory element, wherein the magnetic material pattern or pattern array according to claim 1 is formed from a high coercive force film whose easy magnetization direction is the longitudinal direction of the striped magnetic domain. 5. A Bloch line characterized in that the magnetic pattern or pattern array according to claim 1 is formed from a high coercive force film whose easy magnetization direction is perpendicular to the film surface of the ferromagnetic film. memory element.