JPS60101793A - Magnetic bubble transfer path - Google Patents

Abstract

PURPOSE:To transfer a magnetic bubble which is smaller than a transfer path gap through the gap without any trouble by providing the gap part of a ''Permalloy'' pattern with a magnetic circuit by ion implantation. CONSTITUTION:A rectangular magnetic path 7 which is as wide as gap width delta and long in the arrow-3 direction of chevrons of the pattern 2 is formed at the gap part of the ''Permalloy'' pattern 2 by implanting ions in a magnetic garnet thin film 5. This magnetic path 7 transfers the magnetic bubble which is smaller than the transfer path gap through the gap without any trouble.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a new magnetic bubble transfer path suitable for transferring microbubbles (magnetic bubbles with a diameter of approximately 2 μm or less).

[Background of the invention]

In a conventional magnetic bubble memory device, a magnetic field-driven magnetic bubble transfer path is used, for example, as a magnetic bubble transfer path.
Iza 4 Tenbago Ilnod+ Hanawa (Episode 1:tX 4w
As described on page 100, T
-bar or asymmetric chevron-shaped transfer paths were used. The current quantity is also generally used as an asymmetric chevron pattern, but in this case, the pattern gap δ is λ/8 for the transfer period λ, and the bubble diameter is d = Δ~
It is a valley. When λtS = 8 μm, δ was 1 μm, which reached the limit of conventional photolithography technology, and it was difficult to further increase the density. That is, FIG. 1(a) shows the planar shape of an asymmetric chevron-type transfer path, and a bubble 1 (diameter d is 1.8 μm) passes between the transfer paths with a period λ = 8 μm by an external in-plane magnetic field 3. As the permalloy transfer pattern 2 rotates, it is attracted and repelled by the magnetic poles generated in the permalloy transfer pattern 2 and moves. When the external magnetic field 3 pointed downward in Figure 1, the bubble 1 was able to straddle the gap position and stably occupy that position, as shown in Figure 1, but the bubble 1 It exists in a form that just straddles the potential minimum value and occupies a stable position. FIG. 1(b) shows the cross-sectional structure of such an element, in which a permalloy pattern 2 is placed on a magnetic garnet film 5 grown in a liquid phase on a substrate 4 via a spacer 6. have. Here, with such an element, the period λ
Reducing the size to 4 μm and making it finer is extremely effective in increasing memory capacity and reducing manufacturing costs. However, when λ = 4 μm, the bubble diameter d is 1 μm.
m, and the gap δ is 0.5 μm. With conventional photolithography technology, it is extremely difficult to transfer a size of 1 μm or less, and such a transfer pattern cannot be produced. On the other hand, when λ is set to 4 μm and the gap δ is kept to 1 μm, the following difficulties arise. In other words, Fig. 2 (b
), the bubble diameter is 1 μm, and the bubble cannot straddle the 2 μm gap between the two minimum magnetic potential values and cannot stably exist at the gap position.

In other words, it will exist at either the left or right potential minimum position, and it will be impossible to move across the gap. This means that shift-register type memory operations are completely disabled.

[Purpose of the invention]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a magnetic bubble transfer path that allows magnetic bubbles, which are smaller than the transfer path gap, to be transferred across the gap without any trouble.

[Summary of the invention]

In order to achieve the above object, the present invention is characterized in that a magnetic circuit is provided in the gap portion of the permalloy pattern by ion implantation.

[Embodiments of the invention]

An embodiment of the present invention will be described in detail below with reference to the drawings. In the present invention, as shown in FIG. 3(a), a rectangular magnetic path 7 having a width close to the gap width δ and having a long length in the direction of the chevron arrow is formed in the gap portion of the permalloy pattern 2. It is. This magnetic path 7 is made of magnetic garnet (for example (LaLuSmGd)"(FeGa)' 0.2)
J(2+) is placed on top of the N film 5 (bubble diameter 1 um+?t?' film 1.3 μm).

Implant ions such as "He" (30 to 1 jOKeV.

dose; i=10''), the magnetic path 7 is formed to have a thickness of 0.3 μm (see FIG. 3(b)).

It is magnetized in the film plane and creates magnetic poles according to the direction of the external magnetic field 3. Therefore, when the external magnetic field 3 is directed downward in FIG. 3, the lower part of the magnetic path 7 becomes a magnetic pole that attracts bubbles. Therefore, Figure 3 (c
), the magnetic potential is at its minimum exactly at the gap, allowing the bubble 1 to exist stably and allowing the bubble 1 to move across the gap without any trouble.

As is clear from the above description, the present invention creates a bubble transfer path using a conventional permalloy pattern and an ion implantation pattern formed by implanting ions into the surface region of a magnetic garnet film that retains bubbles. It consists of

〔Effect of the invention〕

Current photolithography technology cannot make the gap in the transfer pattern very small, so if the bubble diameter is made too small, transfer will no longer be possible.

However, according to the present invention, since a transfer path is also formed on the surface of the magnetic film by ion implantation, microbubbles can be transferred without any problems without forcibly reducing the gap. It can be easily formed using technology.

[Brief explanation of drawings]

FIG. 1(a) is a plan view of an asymmetrical chevron-type transfer path;
The same figure (b) shows the sectional view. Moreover, FIG. 1(c) represents the magnetic potential energy that the magnetic bubble receives at each position in FIG. 1(b) on an arbitrary scale. FIG. 2(a) is a plan view of the asymmetric chevron transfer path. Figure 2(b) is a sectional view of Figure 2(0), Figure 2(c)
is an arbitrary scale representation of the magnetic potential energy that the magnetic bubble receives at each position in FIG. 2(b). FIG. 3 shows an embodiment of the invention. FIG. 3(a) is a plan view of the asymmetric chevron transfer path. Figure 3(b) is a sectional view of Figure 3(a), Figure 3(c)
is an arbitrary scale representation of the magnetic potential energy that the magnetic bubble receives at each position in FIG. 3(b). ■...Magnetic bubble, 2...Permalloy pattern. 3... Rotating magnetic field, 5... Garnet 1~film, 7...
Ion implantation pattern (magnetic path), λ...period, d...
·gap. Figure 1 (Bn (C) Continued from page 1 0 Inventor: Ryo Suzuki, Kokubunji City, Higashi Koigakubo Research Institute, 0 Inventor: Product 1) Noriwa, Kokubunji City, Higashi Koigakubo Research Institute, 0 products Akira Sugi 1) Tsune Kokubunji City Higashi Koigakubo Research Institute 0 authors Kodama Naoki Kokubunji City Higashi Koigakubo Research Institute

Claims (1)

[Claims] 1. A magnetic bubble transfer path consisting of a pattern of a soft magnetic film having a desired shape and an ion implantation pattern formed on the surface region of the magnetic film. 2. The ion implantation pattern is formed by providing a magnetic circuit by ion implantation in the gap between each soft magnetic film in the pattern of the soft magnetic film. Magnetic bubble transfer path as described in section.