JPS60242578A - Composite magnetic bubble memory element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention provides a transfer path formed by ion implantation,
The present invention relates to a composite magnetic bubble memory element in which a transfer path formed by a soft magnetic material (for example, permalloy made of an alloy of Ni and Fe) coexists within one chip.

[Background of the invention]

In order to create a memory that guarantees high density, high integration, and complete non-volatility in magnetic bubble memory elements, we use a transfer path formed by ion implantation (hereinafter referred to as ion implantation transfer path) and a soft magnetic material. An element in which a conventional transfer path (hereinafter abbreviated as permalloy transfer path) is combined has been proposed (!!ff Patent Publication No. 57-40791). This is a memory element in which an information storage section is formed using an ion implantation transfer path that facilitates high density, and a functional section for writing and reading information is formed using a permalloy transfer path.

This device requires a connection between the ion implantation transfer path and the permalloy transfer path. FIG. 1 shows the vicinity of a conventional connection part used by the present inventors. The part on the right side of Figure 1 is the connection part from the ion implantation transfer path 3 to the permalloy transfer path, and the part on the right side is the connection part from the permalloy transfer path to the ion implantation transfer path 3. The data is transferred in the direction of arrow 5 indicating the transfer direction. When the direction of the rotating magnetic field 6 applied in-plane is within the range 7 in FIG. will exist. At this time, a magnetic pole that repels the magnetic bubble is generated at the end of the soft magnetic material piece 1 closer to the recess 4 of the ion implantation transfer path. As a result, the upper limit of the bias magnetic field in which the magnetic bubble in the concave portion 4 of the ion implantation transfer path can exist is reduced, and the range of the bias magnetic field is narrower than the range in which the magnetic bubble can exist in the ion implantation transfer path that is fully formed from the connection part. A problem arose.

[Purpose of the invention]

An object of the present invention is to sufficiently control the range of the Paian magnetic field in which magnetic bubbles can exist in the concave portion of the ion implantation transfer path that is closest to the soft magnetic material piece used for the connection part. The objective is to make the range of the bias magnetic field the same as or wider than the range of the bias magnetic field in which a magnetic bubble can exist in the ion implantation transfer path.

[Summary of the invention]

In order to achieve the above objective, the distance between the soft magnetic material piece used for the connection part and the bottom of the concave part of the ion implantation transfer path closest to it is set as a parameter, and a bias is applied so that the magnetic bubble in the concave part can exist. We determined the range of the magnetic field and investigated the optimal positional relationship. Here, the parameter is the length t projected into the film plane of a straight line connecting the end of the soft magnetic material piece and the bottom of the cusp, as shown in FIG.

Figure 2 shows the experimental results. The vertical axis is the magnitude of the bias magnetic field, and the horizontal axis is the parameter t2, the diameter d of the magnetic bubble.
It is the value divided by In the experiment, a magnetic bubble with a diameter of 1 μm was used, and t was varied from 0 μm to 5 μm. For comparison, the upper and lower limits of the bias magnetic field range in which magnetic bubbles can exist in the ion implantation transfer path located at a sufficient distance from the connection portion are also shown. The figure also shows cases where the magnitude of the rotating magnetic field is 6006 and 4006. From this, when the magnitude of the rotating magnetic field is 600e,
It has been found that the above objective can be achieved if t/d is 2.7 or more. It was also found that when the magnitude of the rotating magnetic field is 500e, the above objective can be achieved if t/d is 2 or more.

The reason that the minimum value of 1/d changes depending on the magnitude of the rotating magnetic field is that as the rotating magnetic field increases, the repelling magnetic poles formed in the soft magnetic material pieces become stronger, extinguishing the magnetic bubbles in the recesses of the ion implantation transfer path. This is to make it easier.

FIG. 3 shows the dependence on the rotating magnetic field when t/d is 0.1, 2, 3, and 4.5. The vertical axis represents the magnitude of the bias magnetic field, and the horizontal axis represents the magnitude of the rotating magnetic field. The lower limit of the bias magnetic field range in which magnetic bubbles can exist is t/
It was found that the upper limit value does not depend on d, but depends on t/d and the magnitude of the rotating magnetic field. The range of the bias magnetic field in which magnetic bubbles can exist in the ion implantation transfer path that is sufficiently far away from the soft magnetic material element is shown on the right side of Figure 3 when the magnitude of the rotating magnetic field is constant over 250 e. It is something. From the experimental results, if /, /d≧3, the bias magnetic field range in which magnetic bubbles can exist in the concave portion in question will decrease little, regardless of the magnitude of the rotating magnetic field, and the bias in which magnetic bubbles can exist in the ion implantation transfer path will be small. It turns out that it can be made as wide as or even wider than the magnetic field range.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. The case is shown in which the distance between the tip of the soft magnetic material piece used for the connection portion and the bottom 4 of the concave portion of the ion implantation transfer path closest to the tip is projected into the film plane and is tk 4 μm. When we measured the range of the bias magnetic field in which the magnetic bubbles near the bottom 4 of the recess can exist in this connection part, we found that it is compared to the range of the bias magnetic field in which the magnetic bubbles can exist in the ion implantation transfer path that is far enough from the connection part. Therefore, the upper limit value was increased by 606 and the lower limit value was decreased by 30e, and a wide bias magnetic field range was obtained in the ion implantation transfer path.

FIG. 5 is also one of the examples, and like FIG. 4, t-1(
This is a case where the thickness is 4 μm. Compared to FIG. 4, the boundary of the ion implantation region is located closer to the tip of the soft magnetic material piece. It was found that the same effect as in FIG. 4 was obtained in this case as well.

FIGS. 6 and 7 are also examples, each showing a connection portion from the ion implantation transfer path to the 74-Malloy transfer path. Figure 6 shows t=4μm, Figure 7 shows t=8
The figure shows the case of μm. In both cases, the range of the bias magnetic field (where a magnetic bubble exists near the bottom 4 of the recess of the ion implantation transfer path) is the range of the bias magnetic field where a magnetic bubble can exist in the ion implantation transfer path sufficiently far from the connection. It was found that the range is wide, the upper limit is 606 larger, and the lower limit is 30e smaller.

Similarly, as a result of experiments in various cases, when t/d is 3 or more, the bias magnetic field range in which the magnetic bubble in the concave part of the ion implantation transfer path closest to the connection part can exist is the same as that of the magnetic bubble in the ion implantation transfer path. It was found that the bias magnetic field range is not narrower than the range in which the bias magnetic field can exist.

〔Effect of the invention〕

According to the present invention, the magnetic bubble in the concave portion of the ion implantation transfer path closest to the soft magnetic material piece of the connection part is affected by the bias magnetic field in which the magnetic bubble can exist due to the repulsive magnetic pole generated in the soft magnetic material piece. Without reducing the range, it was possible to equal or increase the range of the bias field in which a magnetic bubble in the ion implant transfer path, located far enough from the connection, could exist.

When the present invention was applied to a magnetic bubble with a diameter of less than 1 μm and 0.15 μm or more, it was found that the same effect as in the case of a magnetic bubble with a diameter of 1 μm was obtained.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing the vicinity of the connection between the ion implantation transfer path and the permalloy transfer path, Fig. 2 is a view showing the range of bias magnetic field where magnetic bubbles can exist with respect to the value of d/l, and Fig. 3 1 is a diagram showing the range of a bias magnetic field in which a magnetic bubble can exist with respect to the magnitude of a rotating magnetic field, and FIGS. 4 to 7 are diagrams each showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Soft magnetic material piece, 2... Ion implantation area for forming an ion implantation transfer path, 3... Ion implantation transfer path, 4... Bottom of recess of ion implantation transfer path, 5.・
・Transfer direction of magnetic bubble, 6... Rotating magnetic field, 7...
Direction of rotating magnetic field. Fig. 1 Fig. 3 Mouth observation Fig. 4 Fig. 5 Fig. 6 Fig. 7

Claims (1)

[Claims] In a composite magnetic bubble memory element in which a first transfer path formed by ion implantation and a second transfer path formed by a soft magnetic material coexist in one chip, The connection part to the transfer path and the connection part from the second transfer path to the first transfer path, which exist at the bottom of the concave part of the transfer path included in the first transfer path and at the place closest to the bottom. The length t obtained by projecting the distance between the bottom of the recess and the tip closest to the tip of the soft magnetic material piece included in the second transfer path into the surface of the film that holds the magnetic bubble is the diameter d of the magnetic bubble.
, the bottom of the recess and the soft magnetic material piece are arranged so that t/d>3.