JPS5947382B2 - bubble magnetic domain element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a bubble magnetic domain (hereinafter referred to as bubble) with improved transfer margin.

) relates to a bubble element with a transfer pattern. More specifically, the present invention relates to a bubble element in which a unit element pattern constituting a bubble transfer pattern has the function of extending a bubble in a direction different from the bubble transfer direction and/or of having the function of making a live wire of the bubble. In memory devices using bubbles, the measurer-minor loop method (hereinafter M/
It is abbreviated as m method.

) has become popular due to its fast information retrieval speed.
M/m type bubble memory devices require a bubble detector, which usually uses a permalloy thin film magnetoresistive element and is provided within the measure loop. The bubble information transferred from the minor loop to the major loop through the transfer gate is transferred as a serial bubble train in the major loop to the bubble detection position, and the presence or absence of bubbles is extracted as an electrical signal. The bubble train that has passed the detection position is transferred as it is within the major loop and returns to the gate position, and the bubbles are transferred to the minor loop again. The above is an explanation of the read operation in a general M/m type bubble memory element. As the density of bubble elements has increased, the diameter of the bubbles used has become smaller, from several tens of microns in orthoferrite systems to several microns in garnet systems.

The bubble detection power is roughly proportional to the bubble diameter, and only a very small detection power can be obtained for minute bubbles. In order to improve this point, the bubble method described in Japanese Patent Application Laid-open No. 108936/1983 was proposed.
This is a detector using a stretcher. A bubble stretcher type detector is a detector that stretches a valve that transfers a measure loop perpendicular to its traveling direction, and effectively utilizes the magnetic flux from the stretched bubble.

The expanded bubble after detection returns to the major loop, but at that time it needs to shrink back to its original bubble size. A typical example of a bubble stretcher having such a function is the Siepron stretcher, which is made of a Siepron-type soft magnetic bubble transfer pattern stacked in multiple layers perpendicular to the direction of bubble propagation, and is disclosed in the above-mentioned Japanese Patent Laid-Open No. 49-1981. Examples can be found in US Pat. No. 108,936 and US Pat. No. 3,702,995. Normally, the number of laminated layers of the Siepron type transfer pattern is gradually increased in the direction of bubble propagation, and after reaching the maximum number, the number of laminated layers is gradually decreased to form a T-bar type, Y-Y type, or It has a structure that allows smooth connection to a transfer path consisting of a single pattern such as a siebron type. In the M/m type bubble device, it is very advantageous to place the detector as close to the transfer gate as possible in order to shorten the information access time. In addition, in order to increase the effective area of the bubble chip (ratio of the area with the bubble transfer pattern to the total chip area) and to increase the degree of freedom in designing functional parts such as the bubble eliminator and generator in the measurer loop, the stretcher part is used. It is desirable to reduce the area occupied by Delicious. For this purpose, it is necessary to increase or decrease the number of laminated stages of the Siepron stretcher. Conventionally, the part to increase or decrease the number of stacked layers of a stretcher pattern was simply to change the number of layers of the pattern. There is only one.

As a result of experiments conducted by the present inventors, it has become clear that in such a case, the margin when the bubble passes through the Siepron stretcher is extremely reduced on the upper limit side of the bias magnetic field. An outline of this will be explained using FIG. 1, taking as an example the reduced number of laminated layers of SIEPROON. In this example, the number of laminated layers of the Siepron stretcher 1 is decreased by two.

The bubbles are transferred in the direction of arrow 5 in response to the clockwise rotation of the in-plane rotating magnetic field HR. When the bias magnetic field for bubble retention is low, the bubbles are transferred as shown in 31 while being extended in the stacked direction of the Siepron according to the number of layers. Even when the bubble reaches the position of the reduced number of steps 2, it has sufficiently expanded as shown at 34, so that it can be successfully transferred to the next layered pattern of Siepron with a reduced number of steps. However, when the bias magnetic field becomes high, even a bubble extending as shown at 31 will shrink to the upper layer of the stack as shown at 32 when it passes through the top of a set of Siepron lamination patterns.

This is because the bubble retaining magnetic field becomes weaker in the lower layer of the SIEPROON stack. Next, the bubble moves to the layered pattern number reducing section 2 while being shrunk. Even if an in-plane rotating magnetic field is applied in a direction that moves the bubbles to the next pattern, the bubble 33 is shrunk because there is no next Sipron pattern at the position corresponding to the step number reduction part 2.
loses his destination and jumps out of the stretcher. For this reason, the transfer margin at the stretcher portion of the bubble is reduced. Furthermore, when the transfer bubble array in the stretcher section is a continuous bubble, the bubbles at the center of the bubble array are more likely to shrink due to bubble-bubble interaction, and therefore the margin of passage becomes extremely small. In other words, a bubble device having such a bubble stretcher type detector in its measure loop has a small operating margin and cannot be a stable memory device. Also, when combining a multi-stage chevron type transfer pattern with a single chevron or Y-Y type pattern, a bubble transfer error similar to the above occurs, and a bubble element with such a transfer pattern similarly has a stable and wide bias magnetic field margin. cannot be obtained.

The purpose of the present invention is to eliminate such drawbacks and to provide a bubble element having a transfer pattern layer number conversion pattern with good pass transfer characteristics.

The present invention will be explained in detail below using the drawings.

FIG. 2 shows a first embodiment in which the finger-like pattern used in the present invention is used in the conventional sieve pattern stacked layer number reduction section shown in FIG. 1, which decreases in steps of two steps. The pattern 20 for converting the number of layers is a finger-like pattern that branches into three on the side of the chevron pattern with a large number of stacked layers, and merges into one on the other side with a small number of stacked layers.

It is provided in the laminated portion of the chevron pattern to form a portion where the number of laminated layers is reduced. As in FIG. 1, the bubble is transferred in the direction of arrow 5 with respect to the clockwise rotation of the in-plane rotating magnetic field. When the bias magnetic field becomes high and the bubble 31 passes through the stacked part of the Siepron pattern, it shrinks at the top of the pattern 3 as shown at 32.
Even when reaching the position indicated by 3, there is a transfer pattern 20' corresponding to the next laminated part of the chevron pattern, and the bubbles will not jump out of the stretcher. In other words, in the bubble stretcher 1, which is made up of a part for reducing the number of laminated layers of the chevron having such a laminated layer number conversion pattern, a large passage margin can be obtained. In this example, 20″, 2
0″″ also uses finger-like patterns, but by using two or more finger-like patterns in this way, a larger margin can be obtained. The same applies not only to the stretcher but also to a simple layer number conversion section. The features of the present invention are:
A finger-like pattern as shown in FIG. 20 is used as the layer number conversion pattern.

The finger-like pattern is a bubble transfer pattern that is a single soft magnetic pattern having a plurality of branches on one side and merging into one on the other side, which is essentially a multi-stage chevron pattern. The present invention is not only used for increasing and decreasing the number of stages of bubble stretch layered layered patterns, but also for layered layered patterns of layered layers such as bubble stretcher layered patterns, Y-Y
It goes without saying that the transfer pattern is used to communicate the half-disk transfer pattern and the multi-stage chevron transfer pattern.

FIG. 3 shows a second embodiment of the present invention, and is an example in which a four-stage chevron transfer pattern 1 and a single-stage chevron transfer pattern are connected using a four-branch finger-like laminated stage number conversion pattern.

Regardless of which side of this transfer pattern sequence the bubbles are transferred from, it is possible to convert the number of bubble expansion stages with a large margin. FIG. 4 shows a third embodiment of the invention.

A three-stage chevron transfer pattern and a single-stage chevron transfer pattern are connected using a three-branch finger-like stage number conversion pattern 20.

FIG. 5 shows a fourth embodiment of the invention.

The two-stage chevron transfer pattern and the single-stage chevron transfer pattern are connected using a bifurcated finger-like stage number conversion pattern 22.

The number of branches of the finger-like stage number conversion pattern used in the present invention is not limited to four or two as used in the second to fourth embodiments, but the number depends on the number of stages to be converted. It can be set arbitrarily.

Moreover, it goes without saying that the multi-layered laminated pattern for bubble expansion is not limited to the chevron shape shown in the above embodiments, but may also be a multi-layered laminated pattern exhibiting a Y-shape or other shapes.

As described above, according to the present invention, a bubble element with very stable margins with few bubble transfer errors can be realized in the step number increasing/decreasing portion of the multi-layer laminated pattern for bubble expansion, such as the bubble stretcher in the major loop.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a stage number conversion part made of a conventional multi-stage laminated pattern for bubble expansion, and FIGS. 2 to 5 are plan views showing some embodiments of the stage number conversion part in the present invention. 1 is a multi-stage laminated pattern for bubble expansion, 2 is a part where the number of stages changes,
20, 20'', 20-21, 22 are the finger stage number conversion patterns of the present invention, 31, 32, 33, 34 are bubble positions, 4
is a bubble transfer path pattern, and 5 is an arrow indicating the bubble transfer direction.

Claims (1)

[Scope of Claims] 1. A bubble consisting of a magnetic material that retains a bubble magnetic domain and a soft magnetic pattern provided on the magnetic material, which magnetizes the soft magnetic pattern with an in-plane rotating magnetic field and transfers the bubble magnetic domain. In the magnetic domain element, a multi-layered first pattern consisting of a soft magnetic film that extends bubble magnetic domains in a direction different from the bubble magnetic domain transfer direction, and a multi-layered layered or single-layer second pattern having fewer steps than this pattern. At least a part of the multi-layer laminated pattern between them has a plurality of branches on the first pattern side, one main branch on the second pattern side, and both are combined in a pattern that has a substantially mountain shape. A bubble magnetic domain element having a transfer pattern having a finger-like pattern. 2. The bubble magnetic domain element according to claim 1, wherein the number of branches of the finger-like pattern is 2 to 5. 3. The bubble magnetic domain element according to claim 1 or 2, wherein the first and second patterns are chevron laminated patterns. 4. The bubble magnetic domain element according to claim 1 or 2, wherein at least a portion of the first and/or second pattern includes a finger-like pattern.