JPS6336073B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a magnetic bubble element,
More specifically, the present invention relates to improving the output of a magnetic bubble detector, which is one of the components of a magnetic bubble element.

As a magnetic bubble detector that converts the presence or absence of a magnetic bubble into an electrical signal, a thick film type detector that utilizes the magnetoresistive effect is usually used. In order to obtain a large detection output, magnetic bubbles are expanded into string-like bubbles several hundred times larger before the detector, and then detected by the detector. Patterns can be formed at the same time as the bubble transfer path, and Because the film is thick, it has the advantage of increasing the allowable value of the control current.

FIG. 1 is a diagram showing the configuration of a magnetic bubble detector. In the figure, D is a detector line that forms a detector, and S is an enlarger that enlarges a magnetic bubble into a string-like bubble. These patterns D and S are formed of a soft ferromagnetic thin film such as permalloy, and are constructed by stacking a large number of chevron patterns in the horizontal direction. H _R is a rotating magnetic field rotating in the same plane,
H _B is a bias magnetic field applied perpendicular to the plane of the paper, and both are external magnetic fields applied from the outside. The magnetic bubble is transferred in the direction of arrow P by the rotating magnetic field H _R . When the magnetic bubble is transferred under the expander S, it is laterally expanded into a string-like bubble. B is one of the string-like bubbles expanded in this way. Also, in the same figure, it is a detector current applied to the detector line from the outside. The detection output is obtained as a voltage output across the detector line D when the string bubble B passes under the detector line D.

In a magnetic bubble detector with such a configuration,
Conventionally, only a string of bubbles transferred at 2-bit intervals was detected, so the rotating magnetic field rotated twice to read out 1-bit information (one bubble). However, recently, in order to double the data read speed, magnetic bubble detectors have been used to detect continuous bubble trains. In this case, one bit of information is read out with one revolution of the rotating magnetic field, doubling the data rate.

When attempting to read out this continuous bubble array using conventional magnetic bubble detectors, the following problems arose.

In FIG. 2, at the time when magnetic bubble B ₁ is detected by magnetic bubble detector line D, the nearest bubble is B ₀ , B ₁ which exists on magnifier pattern S immediately before or after detector line D. . B ₀ ′,
B ₁ ' is the nearest bubble in the case of a conventional 2-bit spacing bubble string. In this case, magnetic bubble B ₁
At the time of detection, the detector line D is affected by the leakage magnetic field from the nearest bubbles B ₀ and B ₁ , which appears as large noise in the detection output. In addition, Λ
is the period of the magnifier pattern. When reading out continuous bubble strings, this large noise (below
(referred to as PGM noise), the practically sufficient S/
The N ratio could not be obtained. As a countermeasure against this PGM noise, it has been proposed to make the period of the Chevron pattern of the expander S before and after the detector line D three times longer or more, and to move the nearest bubbles B ₀ and B ₁ away from the detector line. ing.

As a result of making a prototype of such a pattern, the following problems were found. In other words, the bubble diameter used in the prototype was 1.5 μm, the minor loop pattern period was 6.0 μm, and the enlarger Chevron pattern period was 18 μm, which is three times longer.As a result of evaluating these, PGM noise was suppressed, but As a side effect, as illustrated in FIG. 3, a problem occurred in the H _R - _{H B} margin characteristics. That is, the magnifier pattern is
A bubble transfer error occurred on the lower limit side of H _B , resulting in a large loss in the lower limit of the bias margin. In the figure, M indicates minor loop transfer, E indicates enlarger transfer, and the shaded area indicates an error area.

Therefore, an object of the present invention is to provide a magnetic bubble detector that does not cause a bubble transfer error at the lower limit side of the bias margin even if the period of the expander pattern is made three times longer or more.

In order to achieve the above object, in the magnetic bubble detector according to the present invention, the shape of the chevron pattern is devised to provide three or more bending points in the middle part of the chevron pattern, thereby facilitating the transfer of bubbles. It is characterized by the fact that it is

Hereinafter, the present invention will be explained in detail using Examples. FIG. 4 shows an example of an embodiment for explaining the present invention. A shows an example of a basic transfer path pattern of a minor loop, and its period λ is 6.0 μm. b shows a conventional example of a quadruple long period magnifier chevron pattern at the same magnification as a.
c shows an example of a quadruple period expander chevron pattern according to the present invention. In this example, three bending points A are formed. By doing this, the distance L ₂ can be set to L ₂ λ,
Enables smooth and stable valve transfer. Note that 10 is a chevron pattern.

FIG. 5 shows various examples of chevron patterns according to the present invention. In both cases, the number of bending points is three. The present invention can be similarly applied to each of these patterns.

Note that three or more bending points can be formed,
It can also be applied to part or all of the expander.

FIG. 6 shows another embodiment according to the present invention. This example shows an example in which the present invention is also applied to the chevron pattern of the detector line. The chevron pattern period of the detector line is set to be three times longer or more, and a pattern having three or more bending points as illustrated in FIG. 5 is used. In the example shown in FIG. 6, the chevron pattern shown in FIG. 5d is used for the detector line.

As explained above, according to the present invention, it is possible to easily obtain a magnetic bubble detector using a chevron pattern with a period of 3 times longer or longer, which has less PGM noise and no bias margin loss for a continuous bubble train. can.

In addition, the magnetic bubble detector according to the above explanation is
Although the magnifier pattern before and after the detector line has a period of three times longer or more, the magnetic bubble detector also has the following: It goes without saying that the present invention can be applied in exactly the same way.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a magnetic bubble detector, FIG. 2 is a diagram explaining problems when reading continuous bubble strings, FIG. 3 is a characteristic diagram showing conventional problems, and FIG.
The figure shows an example of an embodiment of the present invention, FIG. 5 shows another embodiment of the Chevron pattern according to the invention, and FIG. 6 shows an embodiment in which the invention is applied to a detector line. It is. S... Magnifier pattern, D... Detector line,
10...Chevron pattern.

Claims (1)

[Claims] 1. In a magnetic bubble detector in which a magnifying device is provided before and after a detector line, a part or all of the magnifying device is
It is formed with a chevron pattern with a period of double length or more, and this chevron pattern has 3 parts in the middle of the pattern.
A magnetic bubble detector characterized by having more than one bending point. 2. The magnetic bubble detector according to claim 1, wherein the detector line is formed of a chevron pattern with a period of three times longer or more, and has three or more bending points in the middle of the pattern.