JPS5855592B2 - magnetic bubble detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention generally relates to a magnetic bubble detection device, and more particularly to a magnetic bubble detection device using magnetoresistive effect.

To give an overview of the magnetic bubble detection device using the magnetoresistive effect, it consists of a single-crystal magnetic plate made of garnet or the like with a perpendicular axis of easy magnetization, and hundreds of steps made of a soft magnetic permalloy film provided on the magnetic plate. Consisting of a bubble expansion pattern and a detection pattern that is similarly provided on the magnetic plate and connected to the bubble expansion pattern, the bubble expansion pattern stretches a circular magnetic domain (bubble magnetic domain) into a serpentine magnetic domain (stripe magnetic domain). This is similar to detecting the presence or absence of a bubble by using the change in electrical resistance of the detection pattern caused by the stray magnetic field from the serpentine magnetic domain.

By the way, the magnitude of the bias magnetic field margin with respect to the driving magnetic field for bubble transfer in a normal transfer path is reduced in a detection transfer path.

In other words, if the bias magnetic field is strong, it will be difficult to expand the bubble in the bubble expansion pattern, whereas if the bias magnetic field is weak, the bubble will expand, but this may cause malfunctions in the detection device and other functional parts. Become.

Therefore, in detecting bubble magnetic domains, it is important that the bias magnetic field margin be obtained to the same extent as the margin in a normal transfer path.

Figure 1 shows a conventional magnetic bubble detection device using asymmetric chevrons, in which a pattern as shown is arranged on a bubble domain material (not shown) made of garnet or the like, and a bias magnetic field is applied to the surface of the magnetic domain material. It is assumed that a rotating magnetic field is applied vertically in the plane from the outside.

In the figure, 1 is a bubble extension pattern consisting of an asymmetrical chevron, 2 is a detection pattern connected to the baffle extension pattern 1 and the detection element has a serpentine shape, and 3 is an asymmetrical chevron following the transfer path.

With the above configuration, the bubble magnetic domain transferred via the transfer path is stretched by the bubble expansion pattern 1 as described above, and is made into a stripe magnetic domain.

This striped magnetic domain is transferred to the detection pattern 2 to provide the necessary detection voltage.

However, in the bubble extension pattern formed by the asymmetric chevrons as described above, the interval 5 between the narrow portions 4 is too wide with respect to the inside of the magnetic domain, so the serpentine magnetic domain is transferred to the narrow portion 4 of the asymmetric chevron. At times, the magnetic domain is cut, and since the area of the asymmetrical part 8 in the asymmetrical chevron is larger than the bubble, the bubble transferred to the tip 6 is lower than the pattern below the force that tries to stretch in the stretching direction. The force of trying to maintain the circular shape is greater, and therefore the bubble cannot sufficiently ride on the tip 7 of the next adjacent pattern, resulting in poor bubble extensibility.

To improve this, it is better to reduce the bias magnetic field, but this can cause bubbles to malfunction in the detector and other functional parts, so special care must be taken when driving at high speeds.

As mentioned above, the asymmetric chevron 3 has drawbacks as a bubble expansion pattern, but as a bubble transfer path, a strong attractive magnetic field is generated at the tip 6, so it has better bubble driveability than the T-I pattern etc. Moreover, it is excellent because it is possible to reduce the bit period.

Figure 2 shows a conventional detection device using chevrons, in which the pattern shown in the figure is arranged on the bubble magnetic domain material as in the previous conventional example, and a bias magnetic field and an in-plane rotating magnetic field are applied externally. It is assumed that

In the figure, 10 is a bubble expansion pattern consisting of chevrons,
Reference numeral 9 denotes a detection pattern connected to the bubble expansion pattern 10, which is a serpentine as in the prior art example, 11 a chevron following the transfer path, and 12 the tip of the chevron.

In this way, when the bubble expansion pattern 10 is a chevron, it is possible to arrange a larger number of stages adjacent to each other than in the case of the asymmetrical chevron, which improves the extensibility of the bubble, but the tip of the chevron Since a strong attractive magnetic field is not generated in the bubble 12, the bubble drivability deteriorates.

The disadvantage of the conventional technology mentioned above is that the smaller the bubble diameter, the more
The larger the driving frequency, the more noticeable this becomes.

Therefore, the present invention aims to improve the above-mentioned drawbacks of the prior art, and its object is to provide a magnetic bubble detection device with excellent bubble driveability and extensibility.

To achieve this object, the present invention has an asymmetrical part on the bubble generation side of the conventional chevron so that the asymmetrical chevron has both good bubble driveability and good bubble extensibility in the chevron. It is formed by an asymmetric parent chevron whose overall shape is approximately L-shaped and whose width in the transfer direction of the asymmetric portion is thinner than that of a conventional asymmetric chevron, and another parent chevron adjacent to the parent chevron. The present invention provides a magnetic bubble detection device having a bubble expansion pattern consisting of a continuous pattern of child chevrons and child chevrons arranged in a space.

Examples will be described below with reference to the drawings.

FIG. 3 shows an embodiment of the magnetic bubble detection device according to the present invention, in which a pattern as shown in the figure is arranged on a bubble magnetic domain material (not shown) made of garnet or the like, and a bias magnetic field is applied to the surface of the magnetic domain material. It is assumed that an in-plane rotating magnetic field is applied vertically so as to rotate clockwise.

In the figure, 14 is a bubble expansion pattern, 13 is a detection pattern that is continuous to the bubble expansion pattern 14, 15° 16.17,
18 and 19 indicate bubble transfer positions.

The bubble expansion pattern 14 consists of a continuous pattern consisting of an asymmetric parent chevron 20 and a child chevron 21 which are deformed as shown.

The asymmetric parent chevron 20 has an asymmetric portion 25 as shown on the bubble generation side of the conventional chevron, and the width of the asymmetric portion 25 in the transfer direction is equal to the asymmetric portion of the conventional asymmetric chevron (the asymmetric portion 8 in FIG. 1). The overall shape is approximately L-shaped.

The child chevron 21 is arranged in a space formed by the parent chevron 20 and another adjacent parent chevron.

The detection pattern 13 connects the ends of each pattern of the bubble expansion pattern 14 composed of a parent chevron 20 and child chevron 21, and connects the parent chevron 20 and child chevron 21 of each pattern as shown in the figure. It is composed of a pattern with a similar shape.

With the above configuration, the bubble magnetic domain at the transfer position 15 transferred via the transfer path is sequentially transferred and stretched to the respective transfer positions 16, 17, 18, and 19 in the bubble expansion pattern 14, and becomes a stripe magnetic domain. be done.

This striped magnetic domain is transferred to the detection pattern 13 to provide the necessary detection voltage.

The width of the asymmetrical portion 25 of each pattern of the bubble expansion pattern 14 is made thin enough to generate a sufficient attractive magnetic field at the tip 24 of each pattern. Good stretchability.

Moreover, in each pattern of the bubble expansion pattern 14,
Since the child chevrons 21 are arranged so as to narrow the gap between the narrow portion 23 of the parent chevron and the adjacent parent chevron, the stripe magnetic domains are not cut at the gap 22.

Furthermore, since a sufficient attractive magnetic field is generated at the tip 24 of each pattern, the single drivability of the striped magnetic domain is good and is almost the same as that of a normal transfer path.

Therefore, the bias magnetic field margin is equivalent to the normal linear transfer margin.

In addition, the gap margin also increases.

On the other hand, since the detection pattern 13 has the same shape as the bubble expansion pattern 14, the attraction magnetic field at the tip 26 of each pattern is stronger than that of a conventional serpentine, and therefore the driveability is good, and the bias magnetic field margin is It is almost the same as stretching pattern 14.

Note that, of course, a conventional serpentine can be used as the detection pattern.

As explained above, according to the magnetic bubble detection device according to the present invention, since the asymmetric chevron is modified and used as the bubble expansion pattern, the driveability of the magnetic domain is good, and the chevron is arranged near the narrow part of the asymmetric chevron. As a result, the magnetic domains will not be severed.

Furthermore, since the detection pattern is configured in the same manner as the bubble expansion pattern, the drive performance of the magnetic domains will not deteriorate.

Therefore, the present invention can be widely used as a bubble memory detection device.

[Brief explanation of drawings]

FIG. 1 shows a conventional example of a magnetic bubble detection device using asymmetric chevrons, FIG. 2 shows a conventional example of a magnetic bubble detection device using chevrons, and FIG. 3 shows an embodiment of a magnetic bubble detection device according to the present invention. 13...Detection pattern, 14...Bubble expansion pattern, 15, 16, 17, 18, 19...
... Bubble transfer position, 20 ... Parent chevron, 21 ... Child chevron, 22 ... Gap, 23 ... Small part, 24 ... ...Tip part, 25...Asymmetrical part.

Claims (1)

[Claims] 1. Stretching a bubble magnetic domain into a striped magnetic domain by a bubble stretching pattern provided on a bubble magnetic domain material having a perpendicular easy axis of magnetization, and detecting the stretched striped magnetic domain as being continuous with the bubble stretching pattern. Transfer to pattern,
A magnetic bubble detection device for obtaining a detection voltage has an asymmetrical part on the bubble generation side of a conventional chevron, and the width of the asymmetrical part in the transfer direction is thinner than that of a conventional asymmetrical chevron, so that the overall shape is approximately L-shaped. It has a bubble expansion pattern consisting of a continuous pattern of child-bearing chevrons consisting of an asymmetric parent chevron of the shape and a child chevron arranged in a space formed by the parent chevron and another parent chevron adjacent to the parent chevron. A magnetic bubble detection device featuring: 2. The magnetic bubble detection device according to claim 1, wherein the detection pattern is a pattern in which the ends of each pattern are connected to each other in a bubble expansion pattern composed of child chevrons, and an asymmetric parent chevron and a child chevron are connected. .