JPS63217592A - Magnetic bubble expander - Google Patents

Abstract

PURPOSE:To prevent malfunction by setting the array of patterns prescribed in an expansion unit in which plural pattern strings where plural angled permalloy patterns are piled up are arranged and disposing auxiliary patterns. CONSTITUTION:The patterns 2 are aligned so that the edges in angled direction in the pattern strings of the angled patterns 2 gradually spread with respect to the direction of bubble travel and stripe magnetic domain is gradually stretched and is set to be widen toward the end. Deep potential is generated on the tips of the patterns and a magnetic bubble is expanded without the detection of a transfer characteristic and with strong stretch power. On the other hand, the auxiliary patterns are provided adjacent to the side of bubble exits 2a in the patterns 2 of the edges of respective strings 3, and the bubbles do not get into the left side of the strings, but cling to the tips of the stable patterns 5 to be pinned. Thus, ring-like deformation of the stripe magnetic domain hardly occurs and the occurrence of malfunction due to deformation can be prevented.

Description

[Detailed Description of the Invention] [Summary] This is a magnetic bubble expander, which has a structure in which the right end of the expander (the mountain side of the mountain-shaped pattern) gradually expands in the bubble traveling direction. By placing a bar-shaped auxiliary pattern on the exit side of the chevron-shaped pattern,
It is possible to suppress wrap-around at the tip of the stripe bubble, making it possible to improve the transfer margin.

[Industrial application field]

The present invention relates to a magnetic bubble expander for a magnetic bubble memory element used in a storage device such as an electronic computing device.

A magnetic bubble memory element is produced by forming a thin film of magnetic garnet by liquid phase epitaxial growth on a non-magnetic substrate such as a single crystal of gadolinium, gallium, or garnet.
On top of that, a bubble transfer path is formed with a matrix of half-disk or chevron-type patterns using a soft magnetic thin film such as permalloy, and bubbles generated by a bubble generator according to information are guided to the transfer path. , information is stored as "1" if there is a bubble in the pattern, and "O" if there is no bubble. To detect information, a detector is usually constructed using a soft magnetic thin film such as permalloy, and bubbles are detected using the magnetoresistive effect. In this case, a magnetic bubble expander is used that stretches the magnetic bubbles into stripes to increase the magnetoresistance change of the detector.

[Conventional technology]

In the conventional magnetic bubble expander, as shown in Fig. 3, a pattern row 3 in which mountain-shaped patterns 2 such as chevrons of soft magnetic thin films are stacked in multiple stages is used as a transfer section for one bit, and this pattern row 3 is used for bubble transfer. The sensor is arranged in multiple rows from the path toward the detector.

[Problem that the invention seeks to solve]

The above-mentioned bubble domain expander must have both strong stretching ability and a wide stripe domain transfer margin. It is necessary to create deep potential in the department,
Conversely, as the pattern period becomes longer, the transfer characteristics tend to deteriorate. As shown in FIG. 4, this deterioration of the transfer characteristics becomes particularly noticeable on the low drive, low bias side as the chip temperature decreases. The cause of this characteristic deterioration will be explained next. Generally, in a chevron-like pattern with a long pattern period, the shape anisotropy between the peaks and the valleys is large, making it difficult for smooth magnetic pole movement to occur, resulting in a decrease in the driving force of the bubble.

Therefore, the entire striped magnetic domain cannot move smoothly, and is transferred in a largely meandering shape as shown in FIG. 5a.

Since the ends of the striped magnetic domains have a greater degree of freedom of movement than other locations, they reach the exit of the chevron pattern earlier than the main body of the striped magnetic domains.

At this time, if the bias magnetic field is low and the stripe magnetic domain tip has already reached the end of pattern row 3, the stripe head starts stretching again toward the empty side of the pattern row (left side in the figure). As shown in the figure, the striped magnetic domain 4 is deformed into a ring shape at the end of the pattern row 3. As a result, the main body of the stripe magnetic domain, which has been delayed in movement, receives repulsion from the magnetic domain on the stripe head side, so it moves even more slowly.Especially on the low drive side where the driving force is decreasing, it cannot reach the exit side and continues to move toward the entrance side. I was drawn back to 2. Splitting into two causes malfunction and deterioration of characteristics.

The present invention was created in view of these points.
The purpose is to provide a magnetic bubble expander that can prevent malfunctions.

[Means for solving problems]

Therefore, in the present invention, as illustrated in FIG.
In a magnetic bubble expander in which a plurality of pattern rows 3 in which a plurality of chevron-shaped permalloy patterns 2 are piled up in multiple stages are repeatedly arranged, the ends of the plurality of pattern rows 3 in the width direction of the chevron-shaped permalloy patterns 2 are bubbles. A bar-shaped auxiliary pattern 5 is arranged so as to gradually expand in the direction of movement of the stripe bubble, and is located close to the bubble outlet side 2a of the chevron-shaped pattern 2 at the end to suppress the tip of the striped bubble from turning around. It is characterized by the fact that it is located.

[For production]

By making the ends of the pattern row 3 widen in the bubble traveling direction and providing the auxiliary patterns 5 at the ends of the eyes and tails, the tips of the stripe magnetic domains attach to the tips of the auxiliary patterns 5 with deep potential, so that the stripe magnetic domains Ring-shaped deformation is suppressed and bubbles can be transferred smoothly.

〔Example〕

FIG. 1 is a diagram showing an embodiment of the present invention.

As shown in the figure, this embodiment differs from the conventional art in that pattern rows 3 in which a plurality of chevron-shaped permalloy patterns 2 are piled up in multiple stages are repeatedly arranged in multiple rows from the bubble transfer path toward the detector. Similarly, the gist of the present invention is
The plurality of pattern rows 3 are arranged in such a way that the ends of the pattern rows in the width direction (right direction in the figure) of the mountain-shaped patterns 2 gradually extend the striped magnetic domain toward the bubble traveling direction, and The par-shaped auxiliary pattern 5 is arranged close to the bubble outlet side 2a of the chevron-shaped pattern 2 at the end of the pattern row.

In this embodiment configured as described above, since the auxiliary pattern 5 is bar-shaped, the potential generated at the point P at the tip thereof is deeper than that of the other chevron-shaped patterns 2. Therefore, the tips of the striped magnetic domains transferred along the mountain-shaped pattern 2 are attached to the tips of the more stable auxiliary patterns 5 and pinned, rather than going around to the left of the pattern row 3, so that the striped magnetic domains are shaped like a ring. Deformation is less likely to occur, and therefore malfunctions as explained in FIG. 5 are prevented.

FIG. 2 shows another embodiment of the present invention, in which two auxiliary patterns 5 are arranged in each pattern row 3 in the one shown in FIG. Three of these are arranged in each pattern row 3, and the other configuration is the same as that of the previous embodiment.

By increasing the number of auxiliary patterns 5 in this way, the tip of the stripe magnetic domain can be moved further away from the chevron-shaped pattern 2 at the right end of the pattern row, and the main body of the stripe magnetic domain, which is transferred later, is transferred more smoothly to prevent malfunctions. be able to.

〔Effect of the invention〕

As described above, according to the present invention, malfunction of the magnetic bubble expander can be prevented with an extremely simple configuration and the transfer margin thereof can be improved, and the present invention is extremely useful in practice.

[Brief explanation of the drawing]

Fig. 1 shows an embodiment of the present invention, Fig. 2 shows another embodiment of the invention, Fig. 3 shows a conventional magnetic bubble expander, and Fig. 4 shows a conventional magnetic bubble expander. FIG. 5 is a diagram showing the transfer characteristics of a magnifying device. FIG. 5 is a diagram showing a malfunction mode at the lower limit of the transfer characteristics in a conventional magnetic bubble expander. In FIGS. 1 and 2, 2 is a chevron-shaped pattern, 3 is a pattern row, and 5 is an auxiliary pattern.

Claims (1)

[Claims] 1. In a magnetic bubble expander in which pattern rows (3) in which a plurality of chevron-shaped permalloy patterns (2) are stacked in multiple stages are arranged repeatedly, the plurality of pattern rows (
3) is arranged so that the end of the mountain-shaped pattern (2) in the mountain direction gradually expands in the direction of bubble travel, and the bubble exit side of the mountain-shaped pattern (2) at the end. A magnetic bubble expander characterized in that a bar-shaped auxiliary pattern (5) for suppressing the tip of the striped bubble from turning around is arranged adjacent to (2a).