JPS6342353B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ion-implanted bubble memory element used as a memory device for electronic computing devices and the like.

As shown in the plan view of FIG. 5 and the sectional view of FIG. 6, the ion-implanted bubble memory element is made of gadolinium.
A thin film 2 of magnetic garnet, which will become a bubble crystal, is formed on a gallium garnet substrate 1 by liquid phase epitaxial growth, and ions such as H, Ne, He, etc. A bubble transfer path is formed by injecting .
In the element formed in this way, the easy axis direction of magnetization of the pattern portion 3 remains as it was, perpendicular to the in-plane direction, as shown by the arrow a, but the ion-implanted region 4
The easy axis direction of magnetization coincides with the in-plane direction as shown by arrow b. Therefore, the bubble 5 is transferred along the periphery of the pattern 3 as shown by the arrow c by the rotating magnetic field. Pattern 3 has a shape in which circles and squares are arranged in a row so that some of them overlap, and unlike conventional permalloy patterns, it does not require a gap, so the dimensional accuracy does not need to be loose, so the pattern can be made small. High density is achieved.
However, this ion-implanted bubble memory element has a seventh
As shown in the figure, there are axes on which bubbles are easily striated out at 120° intervals in three directions, and the above-mentioned connected disk pattern 3 is formed with respect to these easy magnetization axes at 120° intervals. Depending on which direction the disk patterns are lined up in a row, there are three bubble movement paths: super track s, butt track b, and good track g.

[Problems to be solved by conventional technology and invention]

FIG. 8 is a diagram showing an inside turn of a folded minor loop in a conventional ion-implanted bubble memory device having a major-minor configuration.
In the figure, 6 is the ion implantation region, 7 is the bubble transfer path H _R in the driving magnetic field direction, 121, 112, 21
1 indicates the crystal orientation.

This conventional example is a minor loop of the type that turns back from the 121st direction to the 121st direction, and the linear transfer path has a snake-shaped pattern. Note that 121 is 121,1
This is a symbol that collectively refers to 12,211.

This pattern 7 is the transfer section a-
A cusp 8 is included between the b and b, and the bisecting direction of the opening angle of the cusp 8 is 121, which is equal to that of the butt track, resulting in deterioration of the margin. In order to improve this, a shape as shown in Fig. 9 (each symbol is the same as Fig. 8) has been considered, but although this pattern is equivalent to that of 011 and Good Truck, it is still not sufficient, and the cusp The problem is that the aperture angle of 8 is narrow, making it unsuitable for high-density devices (16 Mbit/cm ² or more) that require fine patterns.

[Means to solve the problem]

The present invention provides an ion-implanted bubble memory element that solves the above problems, and its means include:
Stripe difficult axis direction 12 that is part of the folded minor loop of the ion-implanted bubble memory device
In the inside-type folding section that folds back from 1 to the easy axis direction 121, there is no cusp in the transfer path between the straight transfer path on the side where the bubble enters the folded section and the straight transfer path on the side where the bubble exits. This is accomplished by an ion-implanted bubble memory device characterized in that the path is in the shape of a mountain.

[Effect]

In the above-mentioned ion-implanted bubble memory element, there is no cusp between the starting point and the ending point of the folded portion, and the direction of the bisector of the cusp including the starting point and the cusp including the ending point is toward the vicinity of 121. It is equivalent to that of Super Truck,
Improved margins. Furthermore, since the transfer path from the starting point to the ending point of the folding section is mountain-shaped, vibration errors of bubbles between the starting point and the ending point are prevented.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a main part of an embodiment of the present invention. This embodiment is an inside turn that is folded back from the 121st direction to the 121st direction, and the linear transfer path is a folding pattern. In the figure, 10 is an ion implantation region, 11 is a bubble transfer path, H _R is a drive magnetic field direction, and 121, 112, and 211 are crystal orientations, respectively.

In this embodiment, as shown in the figure, the starting point 1 of the folding part is
There is no cusp between 2 and the end point 13,
Only a mountain-shaped tape 14 is provided.

In this embodiment configured as described above, the directions of the bisectors 15 and 16 of the cusp 12 including the starting point of the folded portion and the cusp 13 including the ending point are the same.
Since it goes in a direction near 21, it is equivalent to that of a super truck and the margin is improved.

According to experiments, the relationship between the height of the tape 14 and the bias margin is as shown in FIG. In the same figure, the height of the tape is a, the average diameter of the bubble is d, and the case where a=0 is represented by curve A.
The case of d/2 is shown by curve B, and the case of a=5/6d is shown by curve C. From the figure, it can be seen that if a≧d/2, the low drive low bias side of the margin is improved. Further, when a=0, the margin deteriorates because the bubble vibrates between the cusps 12 and 13 in FIG.

FIG. 3 is a diagram showing the margin of this embodiment in comparison with the conventional example. The diagram shows the rotational driving magnetic field H _D on the horizontal axis.
, the bias magnetic field H _B is plotted on the vertical axis, curve A indicates the bias margin of this embodiment, curve B indicates the margin of the conventional example shown in FIG. 8, and curve C indicates the bias margin of the present embodiment.
The margins of the conventional example in the figure are shown respectively. The sample is a crystal with h=0.6, S _W =0.6, 4πMs=
1050G, H _k = 2700Oe, ion implantation conditions were Ne ⁺ , 30KeV, 1×10 ¹⁴ /cm ² ; Ne ⁺ , 120KeV,
2×10 ¹⁴ /cm ² ; H ₂ ⁺ , 36KeV, 3 of 2×10 ¹⁶ /cm ²
Heavy injection is performed, and the transfer path period is 2 μm (equivalent to 16 M/cm ² ). From the same figure, this example (curve A)
It can be seen that this is the best compared to the conventional example (curves B and C).

FIG. 4 is a diagram showing another embodiment. In this figure, the same parts as in FIG. 1 are designated by the same reference numerals. This embodiment is a continuous disk type transfer path, and is designed based on the same concept as the previous embodiment, and therefore has the same effects.

〔Effect of the invention〕

As explained above, according to the present invention, no cusp is provided between the starting point and the ending point of the folded portion of the minor loop, and only a chevron-shaped tape is provided, so that each cusp including the starting point and the cusp including the ending point are The direction of the bisector of the line is directed to the vicinity of 121, making it equivalent to the super track and improving the margin, and the chevron-shaped tape prevents bubble vibration errors between the start and end points. be.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the essential parts of an embodiment of the ion-implanted bubble memory device of the present invention, FIG. 2 is a diagram showing the relationship between the tape height and bias margin, and FIG. FIG. 4 is a diagram showing another embodiment of the present invention, FIG. 5 is a diagram for explaining a conventional ion-implanted bubble memory element, and FIG. 6 is a diagram showing a comparison of the bias margin with a conventional example. Fig. 5 is a cross-sectional view taken along the - line, Fig. 7 is a diagram for explaining the relationship between the crystal orientation of the bubble crystal and the transfer path, and Figs. 8 and 9 are illustrations of minor loops in conventional ion-implanted bubble memory elements. It is a figure for explaining a folding part. In the figure, 10 is the ion implantation region, 11 is the bubble transfer path, H _R is the driving magnetic field direction, 121, 112, 2
Reference numeral 11 indicates a crystal orientation, 12 and 13 indicate a cusp, and 14 indicates a tape.

Claims (1)

[Scope of Claims] 1. In the inside type folded part where the stripe is folded from the hard axis direction 121 to the easy axis direction 121, which is a part of the folded minor loop of the ion-implanted bubble memory element, the side where the bubble enters the folded part. An ion-implanted bubble memory element characterized in that there is no scum in the transfer path between the straight transfer path and the straight transfer path on the outgoing side, and the transfer path has a mountain shape. 2. The ion-implanted bubble memory device according to claim 1, wherein the height of the mountain-shaped transfer path of the folded portion is 1/2 or more of the average diameter of the bubble.