JPS6226113B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a current access type bubble magnetic domain device. More specifically, the present invention relates to a bubble magnetic domain element in which a bubble magnetic domain is transferred by passing a current pulse train through a perforated conductor layer provided on a bubble material.

In a storage device that uses bubble magnetic domains as information carriers, the bubble magnetic domain transfer method involves applying a chevron-shaped or Y-shaped pattern made of a soft magnetic film such as permalloy to an externally applied in-plane rotating magnetic field. Therefore, the so-called field access method, in which bubble magnetic domains are attracted to magnetic poles generated by sequential magnetization and transferred, has been common.

However, with this field access method, as the bubble domain diameter is reduced to increase information storage density, the in-plane rotating magnetic field required for cylindrical domain transfer increases rapidly, resulting in increased power consumption and It is well known that this method has a major drawback in that the voltage applied to the inner rotating magnetic field generating coil increases, making it unsuitable for high-speed transfer.
Furthermore, as the diameter of the bubble magnetic domain becomes smaller, the minimum dimension necessary for forming a permalloy pattern becomes smaller, and it becomes extremely difficult to manufacture an element using a bubble magnetic domain with a diameter of 2 μm or less.

As a bubble domain transfer method that overcomes the drawbacks of the conventional field access type bubble domain device, a bubble domain device with a current access method was developed by AH Bobeck in August 1979 at The Bell.・The Bell System Technical Journal
Journal), Vol. 58, No. 6, pp. 1453-1540.

The essence of this current access type bubble magnetic domain element is
A rectangular or elliptical through-hole array is created in a conductor layer provided on the bubble material, and when current is passed through the conductor layer, a bias magnetic field distribution generated around the hole is used to drive the bubble magnetic domain. There is a particular thing. Therefore, the bubble domain drive method does not require an in-plane rotating magnetic field and is suitable for high-speed access.

As described in the above-mentioned literature, the current access type bubble magnetic domain transfer method includes a method using a single conductor layer and a method using two conductor layers.
In either method, there are factors that deteriorate the operating characteristics of the bubble magnetic domain element. That is, when a drive current is passed through the conductor layer for driving a bubble magnetic domain, a large bias magnetic field component is generated near the circumference parallel to the current in the conductor layer, and the bubble element operating bias magnetic field margin is extremely reduced in the periphery of the conductor layer. It is a phenomenon. For this reason, only a narrow area in the center of the conductor layer can be used for bubble domain transfer. In other words, this current access type bubble magnetic domain element is not very efficient in terms of chip area.

SUMMARY OF THE INVENTION An object of the present invention is to provide a current access type bubble magnetic domain element which eliminates the above-mentioned drawbacks.

That is, the present invention is a current access type bubble magnetic domain element having a magnetic field compensation conductor layer that reduces a large bias magnetic field component generated from the peripheral portion of the bubble magnetic domain driving conductor layer.

Next, the present invention will be explained in detail while comparing it with a conventional example using the drawings.

FIG. 1A shows a conventional current access type bubble magnetic domain element described in the above cited document.

A bubble material 1 capable of holding a bubble magnetic domain is grown on a substrate material 2, on which a first bubble magnetic domain driving conductor layer 31 is provided, and further on top of that is an insulating layer (not shown). A second bubble magnetic domain driving conductor layer 32 is provided through the bubble magnetic domain drive layer.
An oval hole pattern 30 is provided in the conductor layers 31 and 32. 41 and 42 are the first layer, respectively.
In the current flowing through the second layer, J ₁ and J ₂ represent the respective current densities. 11 is a bubble magnetic domain, and the arrow in the bubble material 1 represents the magnetization direction.

Regarding the conductor layer 31, the current 41 (J ₁ = 1
mA/μm) to generate the bias magnetic field component 10 shown in FIG. 1B. The periphery of the conductor layer 31 has an extremely large magnetic field component, as seen in FIG. 1B. This bias magnetic field component has a large value except in the vicinity 5 of the center of the conductor layer.

In the case of a bubble magnetic domain with a diameter of 2 μm, the bias magnetic field margin where the bubble magnetic domain exists is about 40 to 50 oersteds (Oe), and it is necessary to suppress the reduction in the drive bias margin to about 10%, so the magnetic field due to the current is ±4 to 50 Oe. Must be less than or equal to Ersted. Since the normal drive current density J ₁ is approximately 4 mA/μm, the value of the bias magnetic field component Hg in Figure 1B is ±1
Only the region below Oersted can be used as an actual device. In this example, region 5 is conductor layer 3
It is only about 30% of the width of 1.

The above situation is exactly the same for the second conductor layer 32.

According to the present invention, it is possible to easily increase the conductor area of a bubble element that can be used as this element.

Next, the present invention will be explained using examples shown in the drawings.
In the following description, depiction of through holes in the bubble magnetic domain driving conductor layer is omitted.

FIGS. 2A and 2B show an embodiment of the invention from different angles. The structure of the current access type bubble magnetic domain element according to the present invention is as follows. A bubble chip having a bubble material 1 grown on a substrate material 2 and a bubble magnetic domain driving conductor layer 31 provided thereon is connected to a magnetic field compensating conductor having substantially the same width as the bubble magnetic domain driving conductor layer 31. The bubble chip is placed on a support substrate 6 having a layer 35 with an appropriate insulating gap 36 therebetween.
and the magnetic field compensation conductor layer 35 are attached so that they overlap. The magnetic field compensation conductor layer 35 on the support substrate 6 is divided into a first part 38 corresponding to a current outlet terminal and a second part having a current inlet terminal 37. Part 2 is electrically insulated. Bubble magnetic domain drive conductor layer 3
1 and the magnetic field compensation conductor layer 35 are electrically connected to each other by a technique such as face-down bonding at the end opposite to the portion where the current terminal is located. The portion 38 is connected to the bubble domain driving conductor layer 31 via a conductor portion 40 .

If this embodiment is used, when a bubble magnetic domain drive current is passed through the current terminals 37 and 38, the current 41 flowing through the bubble magnetic domain drive conductor layer 31 and the current 43 flowing through the magnetic field compensation conductor layer 35 are in different directions. On the other hand, since the magnitudes are the same, the unnecessary bias magnetic field component generated in the bubble material 1 part substantially disappears because the magnetic field components from the bubble magnetic domain drive conductor layer 31 and the magnetic field compensation conductor layer 35 cancel each other out. . That is,
In a bubble magnetic domain element with such a configuration,
A region effective for driving the bubble magnetic domain can be obtained over almost the entire area of the bubble chip where the conductor layer for driving the bubble magnetic domain is located.

Furthermore, if this embodiment is used, there is no need to wire the bias magnetic field compensating conductor layer over the bubble magnetic domain driving conductor layer on the bubble chip, making the manufacturing of the bubble chip extremely simple.

In the embodiments of the present invention, the case where the bubble magnetic domain driving conductor layer is one layer has been described to simplify the explanation. However, if the number of bubble magnetic domain drive conductor layers is plural, it goes without saying that the magnetic field compensation conductor layers may also be multilayered correspondingly.

[Brief explanation of the drawing]

FIG. 1A is a perspective view showing a conventional example, and FIG. 1B is a diagram showing a magnetic field distribution in the conventional example. 1 is a bubble material, 11 is a bubble magnetic domain, 2 is a substrate material, 31 and 32 are conductor layers for driving bubbles, 30 is a hole pattern provided in the conductor layer, 41 and 42 are currents for driving bubbles, and 10 is from the conductor layer Distribution 5 of the generated bias magnetic field components is a range having bias magnetic field components that do not have a significant effect on bubble domain transfer. FIGS. 2A and 2B are perspective views showing an embodiment of the invention from different angles. 6 is a bubble chip support substrate, 35 is a conductor layer for bias magnetic field component compensation, 36 is an electrical insulation gap, 3
7 and 38 are current ends, 34 and 40 are electrical contact portions, and 41 and 43 are current directions.

Claims (1)

[Scope of Claims] 1. A bubble chip having a bubble material capable of holding a bubble magnetic domain and at least one bubble magnetic domain driving conductor layer provided on the bubble material through which a bubble magnetic domain driving current flows, is used for driving the bubble magnetic domain. A conductor layer for driving a bubble magnetic domain and a conductor layer for magnetic field compensation are mounted on a supporting substrate having a conductor layer for magnetic field compensation having substantially the same width as the conductor layer so as to substantially overlap each other with an insulating gap in between. , a current access type bubble magnetic domain element characterized by passing current in opposite directions through both conductor layers. 2. The current access type bubble magnetic domain element according to claim 1, wherein the bubble magnetic domain drive conductor layer and the magnetic field compensation conductor layer maintain electrical contact at one opposing end.