JPS6052994A - Magnetic bubble memory element - Google Patents

Abstract

PURPOSE:To improve the bubble transfer characteristic of a minor loop by shifting from 180 deg. a direction of a transfer pattern gap part of the minor loop between adjacent transfer lines. CONSTITUTION:A direction of parallel parts for constituting the gap of adjacent transfer patterns L, R for constituting a minor loop is shifted by further 30 deg., etc. from 180 deg.. Accordingly, as for the transfer characteristic of a magnetic bubble in a gap part, it does not occur that one pattern becomes the best and the other becomes the worst, as is in case the direction is 180 deg., and the overall bubble transfer characteristic of the minor loop is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetic bubble memory device, and particularly to improving the bubble transfer characteristics of a minor loop suitable for a high-density bubble memory chip.

[Background of the invention]

FIG. 1 shows the basic transfer pattern of a minor loop in a conventional magnetic bubble memory element.

As is well known, a transfer path is formed by arranging asymmetric chevron patterns made of soft magnetic material such as permalloy in a row on a bubble magnetic film, and a transfer path is formed on the left side and a transfer path R on the right side.
One minor loop is formed by configuring two rows of in a closed loop. The rotating magnetic field HR is applied to this transfer pattern by arrows 1 to 1.
When applied sequentially in the direction of 1, the magnetic bubbles are transferred over the pattern. The shaded portion in the figure is the magnetic bubble, and the sign of the arrow of the rotating magnetic field HR corresponds to the sign of the position of the magnetic bubble.

However, in the conventional transfer pattern, when the direction of the rotating magnetic field HR is 7 in the right transfer path, the magnetic bubble crosses the gap G1 between the transfer patterns, and in the left transfer path, the magnetic bubble crosses the gap G1 between the transfer patterns when the direction of the rotating magnetic field HR is 3. The bubble crosses the gap G2, but it was found that the transfer characteristics at this time are different between the gaps G1 and GlI.

'That is, as shown in Fig. 2, if the direction of the parallel portions forming the gap between the transfer patterns is determined as shown by arrow A, then if the direction of the parallel portions is in the direction a, a2°a, then the magnetic The magnetic field where the bubble disappears in the gap is not high,
The magnetic bubble becomes difficult to disappear in the gap and the transfer characteristics become good, but when the magnetic bubble is in the b1rbtmbB' direction, the magnetic field at which the magnetic bubble disappears in the gap becomes low and the transfer characteristic becomes worst. Note that when the force is in the C1s C21cl direction, the force value is intermediate between these.

However, al t a! t aB direction, , b
.

, b, and directions are opposite to each other, so if the direction of the parallel portion of the transfer pattern on one transfer path is chosen to be, for example, direction a, the direction of the parallel portion of the transfer pattern on the other transfer path will be The direction will be 180 degrees different.

FIG. 3 is a diagram showing the relationship between the direction of the parallel portion and the nominal magnetic field margin in the gap portion, and there is a difference of ΔH in the transfer margin between the a direction and the b direction. Specifically, this ΔH is 10 to 20 oersteds.

In this way, when a magnetic bubble crosses a gap, the transfer characteristics change depending on the direction of the parallel portion, which is thought to be deeply related to the characteristics of the bubble magnetic film (LPB film) that holds the magnetic bubble and the amount of ion implantation. It will be done. In particular, a, b,
The C direction is closely related to the crystal orientation of the bubble magnetic film formed on the garnet substrate by liquid phase epitaxial growth.

In this way, in the conventional magnetic bubble memory element,
There was a problem that the transfer characteristics of the minor loop were not good.

[Purpose of the invention]

The present invention has been made to solve these conventional problems, and its purpose is to provide a magnetic bubble memory element with good minor loop bubble transfer characteristics.

[Summary of the invention]

In order to achieve such an object, the present invention is configured such that the direction of the parallel portions constituting the gaps in the transfer pattern diagram is deviated from 1800 between adjacent transfer paths.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail using examples.

FIGS. 4(a) to 4(d) show patterns of the left and right transfer paths of the minor loop in each embodiment of the magnetic bubble memory device according to the present invention.

In FIG. 4(a), the direction of the parallel portion forming the gap in the left transfer path is the same as in FIG. 1, but the direction of the parallel portion forming the gap in the right transfer path R is the same as in FIG.
It is different from the illustration. In other words, if the direction of the parallel part on the left side is the direction a, the direction of the parallel part on the right side is 180 degrees from a.
It is set in a direction that is different from b by about 30°, avoiding a b direction that is different from 0. This improves transfer characteristics.

In FIG. 4(b), an asymmetrical chevron is used in which the directions of the parallel portions constituting the gaps in the patterns of the left and right transfer paths are tilted, respectively, compared to those in FIG. Therefore, each direction of the parallel portions is not 180°.

In FIG. 4(C), the direction of the parallel portions constituting the gaps in the patterns of the left and right transfer paths is shown in FIG. 2, 13Hc.
This is in accordance with the optimal direction aSra with a wide margin.

FIG. 4(d) shows an embodiment applied to a case where the gap is not composed of parallel parts. Even in such an example, sufficient effects can be obtained.

Furthermore, the present invention is applicable even when the direction of the parallel portion and the transfer characteristics of the gap are different from those of the above embodiments.

〔Effect of the invention〕

As described above, according to the magnetic bubble memory element according to the present invention, the characteristics when the magnetic bubble crosses the pattern gap on the minor loop transfer path are improved, so that, for example, the transfer rate is 5. to 10 Oe compared to the conventional one. This has the effect of improving the margin and improving the manufacturing yield and performance of the device.

[Brief explanation of the drawing]

Figure 1 is a diagram of the basic transfer pattern of the minor loop of a conventional magnetic bubble memory element, Figure 2 is a pattern diagram showing the direction of the parallel part of the gap, and Figure 3 is the relationship between the direction of the parallel part and the bias magnetic field margin at the gap. Figure 4 (
a) to (d) are seven diagrams of the basic transfer pattern of the minor loop in each embodiment of the magnetic bubble memory device according to the present invention. 1~111I...0 direction of rotating magnetic field, L * # @
@Left transfer path, R-...Right transfer path. Agent Patent Attorney Akira Takahashi No Figure 1 Figure 2 'b+ Figure 3 0, a2 G3 b, b2 b3 C, c2 C3

Claims (1)

[Claims] In a magnetic bubble memory element that has multiple rows of transfer paths each consisting of a basic transfer pattern made of soft magnetic material that constitutes a minor loop that reaches the storage section of a magnetic bubble, the direction of the parallel portions that constitute the gap between the transfer patterns is A magnetic bubble memory element characterized in that transfer paths that meet each other are formed with a deviation from 180°.