JPS63201982A - Magnetic bubble stretcher - Google Patents

Abstract

PURPOSE:To improve the operating margin by forming the pattern of a pattern string in such a way that a pattern at the chevron-shaped head has a small open angle of the leg and a small pattern period and has a large open angle of the leg of the pattern toward the opposite side and a longer pattern period. CONSTITUTION:In a magnetic bubble where many pattern strings 11 with plural chevron-shaped 'Permalloy(R)' patterns 10 overlapped in multistage are arranged repetitively, a pattern A at the head of the chevron pattern 10 of the pattern string 11 is formed such that has a small open angle theta of a leg (b), small pattern period P and has a larger open angle theta toward the opposite side of the pattern string 11 and longer pattern period P. Since the open angle theta of the leg of the pattern A at the end of the pattern string 11 is small in this way, the magnetic field at the head (a) of the pattern is not strong, then the stripe magnetic domain is not stuck and the operating margin is improved at the lower limit of the bias magnetic field.

Description

[Detailed Description of the Invention] [Summary] This is a magnetic bubble expander in which a pattern row of mountain-shaped permalloy patterns is arranged, and the pattern on the head side of the mountain shape has a small opening angle at the foot. In addition, by shortening the pattern period and forming the opening angle of the foot portion of the pattern to become larger toward the opposite side, the pattern period becomes longer, thereby making it possible to improve the operating margin.

[Industrial application field]

The present invention relates to a magnetic bubble expander for a magnetic bubble memory element used in a storage device such as an electronic computing device.

The magnetic bubble memory element is made of gadolinium, for example.

A thin film of magnetic garnet is formed by liquid phase epitaxial growth on a non-magnetic substrate such as a single crystal of gallium garnet, and a pattern such as a half disk type or asymmetric chevron type using a soft magnetic thin film such as permalloy is formed on it in matrix. The bubbles generated by the bubble generator according to the information are guided to the transfer path, and the information is stored as "1" if there are bubbles in the pattern and "O" if there are no bubbles. It is supposed to be done.

In such a magnetic bubble memory element, a method is generally used in which a detector is constructed using a soft magnetic thin film such as permalloy, and bubbles are detected using the magnetoresistive effect of the detector. In this case, to increase the magnetoresistance change, it is common to use a magnetic bubble expander to elongate the bubbles into stripes and introduce them into the detector.

[Conventional technology]

As shown in FIG. 3a, a conventional magnetic bubble expander 1 has a chevron-shaped pattern 2 made of a soft magnetic thin film such as permalloy stacked in multiple stages to form a pattern row 3. A configuration is adopted in which a large number of lines of transfer paths for bits are arranged from the bubble transfer path 4 toward the detector 5.

[Problem that the invention sought to solve]

In the above-mentioned conventional magnetic bubble expander, as shown in FIG. 3, the striped magnetic domains 6 are entangled with the ends of the pattern rows 3, resulting in a rotating magnetic field. It is not transferred correctly for the phase of
Since it is approximately 0e, there is a problem in that this value determines the overall element operation margin.

The present invention was created in view of these points.
The objective is to provide a magnetic bubble expander with improved operating margin.

[Means for solving problems]

Therefore, in the present invention, as illustrated in FIG.
In a magnetic bubble expander 12 in which pattern example 11 in which a plurality of chevron-shaped permalloy patterns 10 are piled up in multiple stages is arranged in a large number of repeated rows, the pattern row 11 is a pattern A located in the cranial direction of the chevron-shaped permalloy patterns 10. The opening angle θ of the foot part is small and the pattern period P is short, and the opening angle θ of the foot part becomes larger and the pattern period P becomes longer as you go toward the opposite side of the pattern row 11. It is characterized by

[For production]

In the pattern A at the end of the mountain-shaped pattern 10 in the pattern row 11 in the head direction, the opening angle θ of the foot part is small, so the magnetic pole at the head a is not strong, so the striped magnetic domains are less likely to get entangled. Errors due to entanglement of striped magnetic domains are prevented and the operating margin is improved.

〔Example〕

FIG. 1 is a diagram showing an embodiment of the present invention.

As shown in FIG. 1, this embodiment uses a magnetic bubble expander 12 in which pattern rows 11 in which chevron-shaped or other chevron-shaped patterns 10 are piled up in multiple stages are arranged repeatedly. The head of the mountain-shaped pattern 10 is a,
Assuming that the foot part is b, the opening angle of the foot part is θ, and the pattern period is P, the pattern A in the cranial direction of the chevron-shaped pattern 10 of the pattern row 11 is the same as the foot part. The opening angle θ is made small and the pattern period P is shortened, and the pattern C located in the side direction of the foot part has a large opening angle θ of the foot part and the pattern period P is made long. The opening angle θ and the pattern period P are changed continuously or stepwise, and the bubble expander has a fan shape.

However, in this embodiment, the opening angle θ of the foot of the pattern A at the end of the pattern row 11 is small, so the magnetic pole at the head a of this pattern is not strong, and therefore the striped magnetic domains are not entangled. The operating margin is improved at the lower limit of the bias magnetic field.

FIG. 2 is a diagram showing another embodiment of the present invention.

The embodiment shown in FIG. It is arranged so that it matches.

In this embodiment configured as described above, the pattern of the magnifying device and the detector has a property that bubbles tend to extend in the direction from the head to the foot of the pattern, so that the upper limit side of the bias magnetic field of the operating margin is improved. Note that crystal orientation ■2r and 2ii are also 1
Similar to 12, the bubble is easy to strike,
A similar effect can be obtained even if the detector 13 is directed in that direction.

In the embodiment shown in FIG. 2, the fan-shaped curvature of the entire bubble expander is relaxed. In a hybrid device using a permalloy transfer path and an ion implantation transfer path as bubble transfer paths, there is no degree of freedom in the placement of the ion implantation pattern, so the placement of the permalloy is uniquely determined. Therefore, the curvature is thick (avoiding the fan shape).

The shape of the chevron-shaped permalloy pattern 10 used in each of the above embodiments is basically a chevron shape, but it can also be applied to other patterns such as a pattern in which two chevrons are connected, a long period chevron, an asymmetrical chevron, etc. .

〔Effect of the invention〕

As described above, according to the present invention, the operating margin of a magnetic bubble expander can be improved with an extremely simple configuration, and is extremely useful in practice.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, FIG. 2 shows another embodiment of the invention, and FIG. 3 shows a conventional magnetic bubble expander. 1 and 2, 10 is a chevron-shaped permalloy pattern, 11 is a pattern row, and 12 is a magnetic bubble expander 1. 13 is a detector. (a) General view Fig. 10 showing an embodiment of the present invention... Convex shape/Turn 11... No. 4 turf row 12... Magnetic/Guple magnifier 13... Detector Other than the present invention FIG. 2 shows an example of 12...Porcelain bubble expander 13...Detector

Claims (1)

[Claims] 1. A magnetic bubble expander (12) in which a plurality of pattern rows (11) in which a plurality of chevron-shaped permalloy patterns (10) are piled up in multiple stages are repeatedly arranged, ) is the mountain-shaped pattern (10
), the pattern (A) has a small opening angle (θ) of the foot (b) and a short pattern period (P), and as it goes toward the opposite side of the pattern row (11), the foot ( b)
A magnetic bubble expander characterized in that the opening angle (θ) of the magnetic bubble expander is large and the pattern period (P) is long. 2. Bubble detector (1) in contact with the pattern row (11)
The direction of the foot side of the pattern in 3) is the crystal orientation @1@@1@
2. The magnetic bubble expander according to claim 1, wherein the magnetic bubble expander is aligned with any one of the following directions: 2, @1@2@1@, or 2@1@1@.