JPH0638312B2 - Magnetic bubble memory device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic bubble memory device, and more particularly to the structure of a magnetic bubble transfer path forming a folded minor loop.

[Background of the Invention]

FIG. 1 shows one minor loop forming a memory area of a magnetic bubble memory element, and a plurality of minor loops of this kind are arranged in parallel in the memory area of the magnetic bubble memory element. . In the same figure, the magnetic bubble transfer path is simplified and shown by a solid line, and the arrow P direction indicates the transfer direction of the magnetic bubble. Such a minor loop is composed of a closed loop transfer path as shown in FIG. As the shape of this closed-loop transfer path, the simple loop type minor loop 1 shown in FIG. 7 (a) to the folding shown in FIGS. Overlapping minor loops 2, 3 and 4 have become popular. The first shape of this folded loop
There are various types other than those shown in Figures (b), (c), and (d). An example of such a folded minor loop is IEEE Trans. MAG-15. No. 6, P1691 to P1696.

As the basic element patterns of the permalloy type transfer path which constitutes such a minor loop, there are the asymmetrical chevron pattern 5 shown in FIG. 2 (a), the half disk pattern 6 shown in FIG. 2 (b), and the same figure (c). The C pattern 7 shown or the club foot pattern 8 shown in FIG.

In the minor loop configured as described above, as shown by the dotted circles in FIG. 1, turn corners for making the transfer direction P of the magnetic bubbles reverse are provided respectively, and these turn corners are provided. 180 in the order shown in the figure
Degree turn corner a and reverse 180 degree turn corner b
There is.

FIG. 3 is a plan view of a main part enlarged pattern showing an example of the transfer path around the reverse 180-degree turn corner part b described above. In the figure, 10a, 10b, 10c, 10d, and 10a 'are magnetic bubble transfer paths forming one folded minor loop, and 11 is a first magnetic path forming the transfer paths 10a, 10b, 10c, 10d, and 10a'. The basic transfer pattern, 12 is the second transfer pattern, 13 is the third transfer pattern, 14 is the fourth transfer pattern, and 15 is the fifth transfer pattern.
12, 13, 14, and 15 form the pattern period and the height of the pattern proportionally larger as the number increases in the direction of the gate portion G, and the transfer paths 10a, 10b, and 10a 'and each of them are formed. A transfer path connecting the gate portion G is formed. 16 is a reverse 180 degree turn corner pattern, 1
Reference numeral 7 denotes the transfer assist pattern. Between the reverse 180-degree turn corner pattern 16 and the transfer paths 10c and 10d, the pattern period and the spine of the pattern are provided on the reverse 180-degree turn corner pattern 16 side as described above. Transfer patterns 11, 12, 13, and 15 that are formed to be large in proportion to the height are connected. Note that P indicates the magnetic bubble transfer direction.

In the transfer path 10b, a pattern 15 larger than the patterns 13 and 14 is arranged between the patterns 13 and 14 as an exception that the pattern size is gradually increased. This is to widen the pattern period in order to reduce the influence of the repulsive magnetic field generated at the right ends of the three patterns 13, 16 and 17 in the transfer path 10c on the left side.

In such a configuration, the magnetic bubble transferred through the transfer path 10d including the basic transfer pattern 11 sequentially transfers the first transfer pattern 11, the third transfer pattern 13, and the fifth transfer pattern 15, and vice versa. The pattern is transferred to the 180-degree turn corner pattern 16, and the reverse 180-degree turn corner pattern 16 causes the transfer direction P to be 180 clockwise.
Then, the third transfer pattern 13, the second transfer pattern 12, and the first transfer pattern 11 are sequentially transferred and transferred to the transfer path 10c. On the other hand, the fifth, the fourth, and the fourth are sequentially arranged on the left side of the reverse 180-degree turn corner pattern 16.
The third and second transfer patterns 15, 14, 13, 12 are the gate part G
To the transfer path 10a 'composed of the basic transfer pattern 11, the magnetic bubbles are transferred in the direction of arrow P. Reverse 1
The fourth, fifth, third and second transfer patterns 14, 15, 13, which are sequentially arranged on the right side of the 80-degree turn corner pattern 16.
Reference numeral 12 transfers a magnetic bubble in the direction of arrow P from the transfer path 10b composed of the basic transfer pattern 11 to the gate portion G.

In order to improve the magnetic bubble transfer characteristics, the reverse 180-degree turn corner portion configured as described above has the cycle of the transfer pattern forming the reverse 180-degree turn corner portion as the pattern cycle of the basic transfer pattern 11 forming the transfer path. And the second, third, fourth, and fifth transfer patterns 12, 13, 14, and 15 that are longer than the same transfer pattern are mixed. For example, the pattern period λ'of the fourth transfer pattern 14 in FIG.
There is a relationship of λ <λ ′ for one pattern period λ. In this way, the second, third, fourth, and fifth transfer patterns 1 whose pattern cycle is larger than the basic transfer pattern cycle
2, 13, 14, and 15 basically have a pattern shape that is a shape in which the basic transfer pattern 11 is proportionally enlarged.
The height of the pattern is higher than the height of the basic transfer pattern. That is, the height h of the basic transfer pattern 20 as shown in FIGS.
₁ and the height h ₂ of the transfer pattern 30 having a long pattern period around the reverse 180-degree turn corner pattern are h ₁ <h ₂
Are formed.

However, since the reverse 180-degree turn corner portion configured as described above is configured with a transfer pattern having a long pattern period around the corner portion, it is known that a transfer error is likely to occur on the lower limit side of the bias magnetic field. It was For example, in FIG. 3, an error occurs in which the magnetic bubble B transferred to the fourth transfer pattern 14 is stripped out to the opposing fifth transfer pattern 15. Then, due to the occurrence of the error, the overall bias field margin of the magnetic bubble memory device is largely limited, as the rotating magnetic field H _R as shown in FIG. 5 increases the error area E is enlarged, the characteristics of the magnetic bubble memory device It was a big problem to damage. Further, the same problem occurs in the vicinity of the above-described forward 180 degree turn corner portion.

[Object of the Invention]

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to eliminate a transfer error generated around a 180-degree turn corner portion and improve a transfer characteristic. It is to provide a bubble memory device.

[Outline of Invention]

In order to achieve such an object, according to the present invention, in a magnetic bubble transfer path in which a transfer pattern having a pattern cycle longer than the basic transfer pattern cycle is mixed in a 180-degree turn corner portion, a transfer having a pattern cycle longer than the basic transfer pattern is performed. The height of the pattern is set lower than that of the basic transfer pattern.

Embodiments of the Invention Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 6 is a plan view of an enlarged pattern of an essential part of the reverse 180 degree turn corner portion for explaining one embodiment of the magnetic bubble memory device according to the present invention. The same portions as those in FIG. Is omitted. In the figure, for example, the fourth transfer pattern 14 'and the fifth transfer pattern 15' having a long pattern period arranged in the peripheral portion of the reverse 180-degree turn corner pattern 16 have a pattern height of the first basic transfer. It is formed to be lower than the height of the pattern 11.
That is, as shown in the enlarged plan views of FIGS. 7A and 7B, the height h ₁ of the basic transfer pattern 20 and the height h ₂ ′ of the transfer pattern 30 'having a long pattern period are shown. Is h ₁ ＞
They are formed with the relationship of h ₂ ′.

According to such a configuration, as shown in FIG. 6, the vertex portion of the fourth transfer pattern 14 'and the fourth transfer pattern 1
Since the distance l between the foot of the fifth transfer pattern 15 'facing 4'is increased, the fifth transfer pattern 15' is increased.
The transfer error in which the magnetic bubble on the fourth transfer pattern 14 'is stripped out due to being attracted to the absorption magnetic poles generated at the foot portion of is eliminated. That is, without being influenced by the attraction magnetic poles generated in other transfer patterns, they are held only by the absorption magnetic poles generated at the apexes of the fourth transfer pattern 14 ', and transferred on this fourth transfer pattern 14'. It will be transferred in the direction P. Therefore, the bias magnetic field margin can be expanded.

In addition, in the above-described embodiment, the case where the height of the transfer pattern having a long pattern cycle is set lower than the height of the basic transfer pattern has been described, but the present invention is not limited to this. Of course, even if the distance l described above is expanded by using a transfer pattern in which the apex portion of the transfer pattern having a long pattern cycle is eccentric in the magnetic bubble transfer direction or in the opposite direction, the same effect as described above can be obtained. Is.

Further, in the above-described embodiment, the reverse 180-degree turn corner portion has been described, but the present invention is not limited to this, and even if it is applied to the forward 180-degree turn corner portion, the same effect as the above is obtained. Of course, it can be obtained.

Further, in the above-described embodiment, the case where the Sieblon pattern is used for the transfer pattern has been described, but the present invention is not limited to this, and FIG. 2 (b), (c),
Of course, even when applied to the transfer path composed of the half-disk pattern 6, the C pattern 7, and the club foot pattern 8 shown in (d), the same effect as the above can be obtained.

〔The invention's effect〕

As described above, according to the present invention, it is possible to eliminate the transfer error occurring in the 180-degree turn corner portion and expand the bias magnetic field margin, so that it is possible to obtain a magnetic bubble memory element having high quality and reliability. It has an extremely excellent effect.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of a minor loop, FIG. 2 is a diagram showing an example of its transfer pattern, and FIG. 3 is an enlarged pattern plan view of an essential part showing an example of a conventional reverse 180-degree turn corner portion. FIG. 5 is an enlarged plan view showing an example of a conventional transfer pattern, FIG. 5 is a diagram showing a transfer characteristic of a conventional reverse 180-degree turn corner portion, and FIG. 6 is an embodiment of a magnetic bubble memory device according to the present invention. FIG. 7 is an enlarged plan view of an essential part of the periphery of the reverse 180-degree turn corner portion for carrying out, and FIG. 7 is an enlarged plan view showing an example of the transfer pattern according to the present invention. 1 ... Simple loop type minor loop, 2, 3, 4 ... Folded type minor loop, 5 ... Asymmetrical chevron pattern, 6 ... Half disk pattern, 7 ... C pattern, 8 ... Club foot pattern, 10a , 10a ', 10b, 1
0c, 10d ... Magnetic bubble transfer path, 11 ... First basic transfer pattern, 12 ... Second transfer pattern, 13 ... Third transfer pattern, 14 ... Fourth transfer pattern, 15
...... Fifth transfer pattern, 20 …… Basic transfer pattern,
30 '... Transfer pattern with a short pattern height and a long pattern cycle.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Minoru Hiroshima 3300 Hayano, Mobara, Chiba Prefecture, inside the Mobara Plant, Hitachi, Ltd. (72) Inventor Tetsuaki Suzuki, 3300 Hayano, Mobara City, Chiba, Ltd. 72) Inventor Hisaya Keida 3300, Hayano, Mobara-shi, Chiba, within the Mobara Plant, Hitachi, Ltd. (72) Inventor, Seiichi Nishiyama 3300, Hayano, Mobara, Chiba, Ltd., within the Mobara, Hitachi, Ltd. (72) Inventor, Mitsuru Sekino Tokyo 1479 Kamimizuhonmachi, Kodaira-shi, Hitachi In-house Hitachi My Cross-Computer Engineering Co., Ltd. (72) Inventor Toshiya Kadoyama 1479, Kamisui-honmachi, Kodaira-shi, Tokyo In-house Hitachi My Cross-Computer Engineering Co., Ltd.

Claims (1)

[Claims] 1. A device for changing the transfer direction of a magnetic bubble 180.
In a magnetic bubble memory device having a magnetic bubble transfer path in which transfer patterns whose pattern period is longer than the basic pattern period are mixed around the turn corner portion, the height of the transfer pattern with the long pattern period is set to A magnetic bubble memory device characterized by being formed to be lower than the height of a transfer pattern.