JPS5927997B2 - Transfer gate for magnetic bubbles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic bubble transfer gate used for transferring magnetic bubbles between a major loop and a minor loop of a bubble memory.

Some bubble memory devices have a read/write shift register called a major loop and a plurality of information storage registers called a minor loop, and both loops are connected by a transfer gate.

This transfer gate is actuated by a transfer signal during reading to transfer the magnetic bubble on the minor loop to the mager loop, and has the role of transferring the magnetic bubble from the mager loop to a desired minor loop and storing it in the desired minor loop during writing. Conventional transfer gates of this type include a basic one using a chevron pattern as shown in Figure 1a, and an improved version using a half disk as shown in Figure 2a. Yes, the latter is often used these days. The transfer gate shown in FIG.
It consists of a major loop 2, a minor loop 3, and a hairpin-shaped conductor 4 located between these and a substrate via an insulating layer. When a driving magnetic field HD rotating counterclockwise as 1, 2, 3, 4 as shown in FIG. 1b is applied to this transfer gate, the magnetic bubble 5 moves from 1→2→as shown in FIG. 1a as the magnetic field changes. 3, 4 → 1...
...and moves to the right in the major loop and to the left in the minor loop. In bubble transfer, for example, when a bubble that has propagated to the right through the Meijer loop 2 comes to the center line of the hairpin-shaped conductor 4, a current is applied to the conductor in such a direction that the inside of the conductor 4 is attracted and the outside is repelled. Flow. At this time, the driving magnetic field HD is 4
In the major loop 2, the top of the chevron pattern 2a is suction, and in the minor loop 3, the top of the chevron pattern 3a is repulsive. From this point on, current is applied to the conductor 4 until the 1800 drive magnetic field rotates. At 1800 rotations, the driving magnetic field points in the direction of 2,
The top of the Chevron pattern is repellent in the Meijer loop,
In the minor loop, the current is cut off when attraction occurs.

Then, due to the attractive magnetic pole created by the current, the bubble that had been extending over the chevron pattern 2a 33a of both major and minor loops inside the hairpin-shaped conductor 4 contracts so that it extends only along the chevron pattern 3a on the minor loop side. . In other words, it moves away from the major loop and moves to the minor loop, and thereafter is transferred to the left through the minor loop as the driving magnetic field rotates. The same goes for the bubble transfer from the minor loop to the magia loop; when the bubble is transferred through the minor loop and reaches the top of the siebron pattern 3a, which overlaps with conductor 4, the bubble transfers to conductor 4.
A current is applied so that the inside of the conductor becomes attracted, and the driving magnetic field rotates by 180 degrees, and the top of the siniplon pattern 2a, which faces from the direction of 2 to the direction of 4 and overlaps with the conductor 4 of the magia loop 2, is attracted, When the top of the apron pattern 3a becomes repulsive, the current is cut off.

As a result, the bubble that had been extended across both patterns 3a, 2a is contracted by the magnetic field created by the current in the conductor 4, and now extends only along pattern 2a. In other words, it is transferred to the magia loop side. In a transfer gate using such a Sipron pattern, when performing bubble transfer, it is necessary to extend the bubble across both patterns 2a and 3a on the center line of the hairpin conductor as described above.On the other hand, the bubble is exposed to a strong bias magnetic field. If the bias magnetic field becomes strong, the transfer tends to shrink, which has the disadvantage that the transfer cannot be carried out smoothly.

In fact, when we draw a margin curve with the drive magnetic field HD on the horizontal axis and the bias magnetic field HB on the vertical axis, we observe that the margin becomes narrower on the high bias side, as shown by the dotted line, as shown in Figure 1c. be done. Another drawback is that the area occupied by the transfer gate is large. In the transfer gate using the half disk shown in Fig. 2a, the driving magnetic field is 1,
When the bubble rotates counterclockwise in the order of 2, 3, 4, 1, . . ., the bubble makes a U-turn on the major loop 2 to the right in the figure and on the minor loop 3 in the direction of the arrow.

To transfer the bubble from the magia loop 2 to the minor loop 3, the driving magnetic field HD is
In other words, when facing in direction A between 1 and 2, a current is passed through the conductor 4 so that the inside is repulsive and the outside is attractive. This magnetic field causes the bubble to extend over the pattern 6a, the bar pattern 7b, and the minor loop half disk pattern 6b overlapping the conductor 4, as shown by the dotted line. When the driving magnetic field HD is directed in the direction 3 and an attractive magnetic pole is formed at the right end of the bar pattern 7b, when the current flowing through the conductor 4 is cut off, the bubble contracts and is attracted near the right end of the bar pattern 7b. Next, when the driving magnetic field turns in four directions, the bubble moves to the vicinity of the upper end of pattern 8b, and as the driving magnetic field further rotates 1, 2, 3, and 4, the bubble moves to the right edge of pattern 8b, the lower end of pattern 8b, and the lower end of pattern 7d. It moves to the right end, half disk pattern 6c, and is thus transferred from major loop 2 to minor loop 3. The same applies to the case of transferring the bubble from the minor loop 3 to the major loop 2, and when the bubble moves in the patterns 6d, 7c, and 6b, a current is passed through the conductor 4.

The direction of this current is repulsion on the inside of the conductor 4 and attraction on the outside, and the period of current flow is from around point B between points 3 and 4 to point 1. 1 When the driving magnetic field HD faces direction 1, when the current is cut off, the bubble is attracted to the left end of the bar pattern 7a, and thereafter the driving magnetic field is 2, 3, 4, 1, etc.
When rotating, the bubble moves from the lower end of pattern 8a, to the right edge, to the upper end, to the left edge of pattern 6e, and so on.

This transfer gate using a half disk has the advantage that it occupies a small area on the memory element, but has the disadvantage that as the current flowing through the hairline conductor 4 becomes large, the margin on the side where the bias magnetic field is weak becomes narrow.

That is, as shown in Figure 2c, the current flowing through the conductor is 10
When the current was about mA, the margin characteristic was a solid line curve, but when the current was increased to 20 mA, the curve on the low bias magnetic field side became higher as shown by the dotted line, and the margin became narrower. The exact cause of this is not clear, but it is thought that the half-takes 6a and 6b are probably magnetized by the current flowing through the conductor 4, and therefore pull back the magnetic bubbles that are trying to be attracted to the ends of the bar-shaped patterns 7A and 7b. It will be done. The present invention has been made for the purpose of providing a transfer gate with a new structure that solves the disadvantages of conventional transfer gates. In addition to providing two half disks for transferring magnetic bubbles, protrusions are provided at the opposing vertices of these half disks in a direction that approaches each other in order to smoothly transfer magnetic bubbles between the two protrusions and prevent a decrease in the margin. It is something to do. The transfer gate for bubble memory of the present invention will be explained in detail below with reference to the embodiment shown in FIG. In FIG. 3a, 2 indicates a major loop, and 3 indicates a part of a minor loop, both of which are made of a half-disc-shaped permalloy pattern 6. 4 is a hairpin-shaped conductor, and 7 is a rod-shaped permalloy pattern.

In the present invention, a protrusion K. G is provided so that these patterns 6a and 6b face each other, that is, a vertex protrusion K. These half-disk transfer pacoons 6a and 6b are arranged so that the vertices G face each other and the apexes and therefore the center line of the half-disk coincide with the center line of the hairpin-shaped conductor 4. To explain the operation, the bubble has major loop 2 and minor loop 3 as mentioned above.
However, for bubble transfer from the major loop to the minor loop, when the driving magnetic field 1 is directed in the direction 2 and the bubble comes to the apex protrusion K of the half disk pattern 6a, the hairpin-shaped conductor for transfer 4, a current is passed in the direction such that the inside of the conductor is attracted and the outside is repelled.

This current causes the rotating magnetic field to rotate 180 degrees from the direction 2 to the direction 4 as shown with diagonal lines in FIG. When the apex protrusion G of pattern 6b changes from repulsion to attraction, the current is interrupted. As a result, the bubble that had been stretched near the protrusions K and G by the current flowing through the conductor 4 moves to the protrusion G, which has become an attractive magnetic pole, and thus a bubble transfer from the major loop to the minor loop, ie, transfer out, is performed. It will be done. The bubble transfer from the minor loop 3 to the major loop 2 is similar, causing current to flow through the conductor 4 when the bubble is at the protrusion G of the pattern 6b.

The direction of this current is also such that the inside of the conductor is attracted, and it continues to flow for 1800 rotations until the drive magnetic field HD changes from the 4th direction to the 2nd direction. When the driving magnetic field HD is oriented in two directions, the protrusion G is repulsive and the protrusion K is attractive, so the bubble moves to the protrusion K, thus performing bubble transfer from the minor loop to the major loop. The apex protrusion K. of the half disks 6a, 6b. G is
As mentioned above, it plays the role of transferring bubbles,
The length of the protrusion is preferably about 1/4 of the height of the half disk pattern.

If the protrusion is too large, it will become an obstacle when the bubble is transferred through the major or minor loops. Projection K. Since these create magnetic poles of opposite polarity, there is no problem with the circulation of only the major loop or only the minor loop of the bubble, and therefore the distance between G can be made quite close. The bar pattern 7 is a transfer magnetic pattern interposed in the half disk pattern 6 in order to smoothly transfer bubbles in each major or minor loop, and these patterns are known. As explained in detail above, the transfer gate of the present invention allows the transfer of magnetic bubbles between half disks having protrusions arranged opposite to each other, and the bubble transfer is carried out outside the hairpin-shaped conductor. Since the current is caused to flow inside the hairpin-shaped conductor, more specifically, along the center line, the magnetic bubble can be transferred reliably, and the permissible width of the current flowing through the hairpin-shaped conductor is wide. In other words, regarding the transfer failure of magnetic bubbles due to local magnetization of half disks, which was a problem with conventional transfer gates using half disks, even if both edges of patterns 6a and 6b were magnetized, the magnetic bubbles would not be transferred to both protrusions. K. This is not a problem because the transfer occurs between G and G. On the other hand, since both protrusions are located almost in the center of the current path of the hairpin-shaped conductor, the magnetization acts in the direction of canceling them, and they are not magnetized to the extent that they cause transfer problems. It is. In addition, in the transfer gate of the present invention, it is necessary to transfer the magnetic bubble between the opposing protrusions and to extend the magnetic bubble long inside the hairpin-shaped conductor. Therefore, it is possible to eliminate the conventional drawback that the magnetic bubble contracts when the bias magnetic field is strong. Furthermore, it maintains the excellent effect of occupying a small area in the memory element, similar to the conventional transfer gate using a half disk.

[Brief explanation of drawings]

FIGS. 1 and 2 are diagrams explaining a conventional transfer gate, in which a is a schematic plan view of the gate, and B and c are explanatory diagrams of the driving magnetic field and margin characteristics. Figure 3 is a diagram illustrating the transfer gate of the present invention.
is a schematic plan view, and b and c are explanatory diagrams showing the timing of the current flowing through the hairpin-shaped conductor.] In Fig. 0, 2
3 is a minor loop, 4 is a hairpin conductor, and 6 is a half 2-isk pattern.

Claims (1)

[Scope of Claims] 1. A hairpin-shaped conductor for bubble transfer control, and two half-disk-shaped permalloy patterns for magnetic bubble delivery facing each other and centered on the center line of the conductor, the permalloy pattern being A transfer gate for a magnetic bubble, characterized in that opposing vertices thereof each have protruding portions in a direction approaching each other. 2. The transfer gate for magnetic bubbles according to claim 1, wherein the protruding length of the protruding portion is approximately 1/4 of the height of the half-disc-shaped permalloy pattern.