JPS645396B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a bubble magnetic domain (hereinafter simply referred to as bubble).
Regarding elements.

Conventionally, bubble devices have adopted a method in which soft magnetic patterns are provided on a bubble retaining layer with a gap between them and bubbles are transferred by in-plane magnetic field rotation. However, the gaps in the pattern are undesirable because they reduce bubble density, impede high-speed bubble transfer, and limit pattern microfabrication.

On the other hand, US Pat. No. 3,828,329 proposed an element that transfers bubbles using a gapless pattern, and its development has been progressing rapidly recently. Therefore, the pattern is formed by ion implantation.
Since the transfer pattern of that element was in the shape of a series of circles, contagious disks (hereinafter referred to as
(referred to as CD) element.

In this CD element, an in-plane magnetization layer is provided on the bubble retention layer, and a magnetic charged wall is generated within the in-plane magnetization layer to transfer bubbles. This in-plane magnetization layer usually has crystal anisotropy, so
The CD element is manufactured by IE Transactions on Magnetics (IEEE
Trans.Magn.) Volume 15 (1979) No. 1323
As stated in the page (hereinafter referred to as the document),
Transfer has different characteristics depending on the crystal plane orientation of the transfer path. In particular, the transfer path perpendicular to the in-plane hard magnetization axis and on the side of the hard magnetization direction is a bad track, the transfer path on the opposite side is a super track, and the transfer path parallel to the hard magnetization direction is a good track. ) tracks, and bubble transfer is known to be worst in butt tracks and best in super tracks. Good track and super track are mainly used in CD devices, but poor transfer characteristics in bad track are an obstacle to making CD devices work.

As for the transfer pattern of the butt track, in addition to the normal pattern of a series of circles, the diamond pattern with the rising part forming an angle of 45 degrees as shown in Figure 1, and the roof top pattern shown in the above-mentioned document. Attempts to improve transfer are known. However, since the roof top pattern has small pattern elements and large pattern elements arranged alternately, there are still some drawbacks, such as difficulty in designing the configuration of functional parts and large patterns causing many transfer errors. However, at present, no other effective improvement measures are known.

The present invention has a pattern shape that alleviates the drawbacks of the transfer characteristics of the conventional pattern of the butt track.
The purpose is to provide CD elements.

According to the present invention, in a CD element in which an in-plane magnetization layer is provided on a bubble retaining layer to form a transfer pattern, and bubbles are transferred along the pattern by the magnetic charge wall of the in-plane magnetization layer, in-plane magnetization In the transfer path perpendicular to the difficult direction and on the side of the difficult magnetization direction, pattern elements are periodically connected without gaps, and two rising parts of each pattern element are at an angle of about 30 to 40 degrees with respect to the difficult magnetization direction. A bubble element formed at an angle of .

Hereinafter, the present invention will be explained in detail using examples.

Embodiment 1 FIG. 2 shows an example of a transfer pattern of the present invention. Here, the pattern is perpendicular to the direction of difficult magnetization 21 shown by the black circle around the circle at the bottom corner of FIG. 2, and the transfer path (butt track) on the side of the difficult magnetization axis 21 is shown by diagonal lines. In the pattern of this example, the angle between each of the two rising portions of pattern elements that are periodically connected without gaps and the difficult magnetization direction 21 is approximately
I chose 30°. For bubble transfer experiments using this transfer path, a Gd ₃ Ga ₅ O ₁₂ (111) single-crystal substrate with a thickness of approx.
A bubble retention layer made of (SmLuBiCa) ₃ (FeGe) ₅ O ₁₂ garnet with a 2.0 μm stripe width of approximately 1.7 μm and a saturation magnetization of approximately 520 Gauss was used. In this example, it is further made of (GdSmTmCa) ₃ (FeGe) ₅ O ₁₂ garnet with a thickness of about 0.5 μm, a saturation magnetization of about 590 Gauss, and a Q value of about 2.0.
drive layer was used. Add He ⁺ ions on top of this
A CD element was formed by implanting 140 KeV and 5×10 ¹⁵ /cm ² .

The quasi-static simple transfer margin of the 8 μm periodic pattern of this embodiment is shown by the solid line 51 in FIG. In Figure 5, the horizontal axis
Hr is an in-plane rotating magnetic field, and the vertical axis Hz is a bias magnetic field. A broken line 53 in FIG. 5 shows the result of the diamond pattern in FIG. 1 for comparison.
In both cases, the margin is shown when the center loop of three parallel loops with 10 bits on each side goes around the bubble. Here, it can be said that the supertrack and corner margins are sufficiently wide, and FIG. 5 shows the butttrack margin. As shown in FIG. 5, in the bubble transfer margin of the butt track, in the example pattern, errors within the cusp are smaller than in the conventional diamond pattern, and a transfer improvement effect is recognized.

Example 2 In the case of FIG. 3 in which the angle between the rising part of the pattern element and the direction of difficult magnetization 21 is larger than that in Example 1 to 40 degrees, the quasi-static simple transfer margin is as shown by the dashed-dotted line 52 in FIG. The conventional diamond pattern (Fig. 1) is narrower than that of Example 1.
Compared to the results of (broken line 53 in Figure 5), a transfer improvement effect is recognized.

Furthermore, the quasi-static simple transfer margin in the case of FIG. 4 in which the angle formed between the rising portion of the pattern element and the difficult magnetization direction 21 is further increased is the dotted line 54 in FIG.
As shown in Figure 2, the results obtained were inferior to those of the conventional diamond pattern. That is, this shows that the pattern forming conditions of the present invention are important.

Example 3 In Examples 1 and 2, the bubble retention layer has a thickness of approximately 0.8 μm, a stripe width of approximately 1.0 μm, and a saturation magnetization of approximately 700 Gauss, and the drive layer has a thickness of approximately
0.4μm, saturation magnetization approximately 590 Gauss, Q value approximately 1.3,
The ion implantation conditions were 100KeV and 3× ¹⁰¹⁵ / ^cm2 ,
Among the experimental films that differed in that the pattern period was 4 μm, the bubble transfer margin of the butt track of the example pattern of the present invention (Figures 2 and 3) was sufficiently improved in transfer compared to the conventional diamond pattern. .

As described above, according to the present invention, it is possible to obtain a CD element having a pattern shape that alleviates the drawbacks of the transfer characteristics of conventional patterns in the butt track of the CD element.
This has a great effect on making the device function. Note that the pattern is rounded by pattern formation, and the pattern shape of the present invention naturally includes this kind of rounded pattern shape.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a conventional pattern of a bubble track, FIGS. 2, 3, and 4 are diagrams each showing an example pattern of the present invention, and FIG. 5 is a diagram showing a quasi-static simple transfer margin of a bubble. FIG. In the figure, 21, 22, and 23 are the three directions of difficult magnetization, 51 and 52 are the transfer margins of Examples 1 and 2, 53 is the transfer margin of the conventional pattern, and 54 is the transfer margin of the pattern in FIG. represent

Claims (1)

[Claims] 1. A transfer pattern is formed by providing an in-plane magnetization layer of a magnetic garnet {111} film on the bubble magnetic domain holding layer, and a magnetic field is applied in the direction opposite to the easy magnetization direction of the in-plane magnetization layer (referred to as the difficult magnetization direction). In a contiguous disk bubble magnetic domain element in which the bubble magnetic domain is transferred along the pattern by the magnetic charge wall that is most prominently formed when The pattern elements are periodically connected without gaps, and
A bubble magnetic domain element characterized in that two rising portions of each pattern element are formed so as to form an angle of about 30 to 40 degrees with respect to the difficult magnetization direction.