JPS5998386A - Magnetic storage element - Google Patents

Abstract

PURPOSE:To attain erasure of a desired vertical Bloch line pair indeqendently of an information string by providing a planer magnetizing layer and injecting one Bloch point of a vertical Bloch line pair. CONSTITUTION:In applying a planer rotating field to a plane magnetizing layer 32 extended over a major loop, a stripe domain is extended and reaches the end of a minor loop 31. In taking off the planer rotating field succeedingly, the magnetization of a vertical Bloch line (VBL) in the layer 32 is inverted partially by a floating magnetic field from a stripe domain storage layer, and the Bloch point being the boundary section is injected, the direction of the magnetization of the VBL34 is inverted and becomes the same direction as the other VBL pairs remaining at the outside of the layer 32. Then, the VBL pairs in the same direction are approached and combined on the loop 31 and a pair of the VBL pair is erased. The desired VBL pair is erased by injecting one Bloch point of the VBL pair desired to be erased via the planer rotating field, independently of the information train, even if the VBL pairs are not continuous.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vertical Proch line that exists statically and stably within a Bloch domain wall that forms the boundary of a stripe domain formed in a soft magnetic thin film whose easy magnetization direction is perpendicular to the film surface. The present invention relates to a magnetic memory element using as a memory unit.

The development of magnetic bubble elements is actively being carried out in various places with the aim of increasing the concentration and speed of permalloy devices, ion-implanted continuous disk devices, current drive devices, and so-called hybrid devices that combine these devices. There is. It has been said that the limit to the high density of these devices lies in the photolithography technology used to form bubble transfer paths. However, in recent years, the technology has advanced rapidly. As a result, the material for densification, i.e.
The question is now how small the bubble diameter can be made. With the garnet materials currently in use, the minimum attainable bubble diameter is said to be 0.3 μm. Therefore, a bubble material that retains bubbles with a diameter of 0.3 μm or less must be found other than garnet material. This is not so easy, and it is even believed that this is the limit of bubble densification.

On the other hand, a memory element has been proposed which can significantly improve the density limit based on the characteristics of such a bubble retaining layer and can keep the time required to release the bubble c to the same level as that of conventional elements.

FIG. 1 is an overall view of this magnetic memory element. To show the overall flow of information, first, the information written by the generator l (the presence or absence of bubbles) moves from the top of the write major life fr to the bottom. In order to store this information in the minor loop 2, the minor loop iV is used so that the information on the major line indicated by the presence or absence of the bubble 3 can be transferred to the minor loop in the form of a vertical Ploch line (VBL).
B L' (consists of Bloch domain walls that can maintain z. Information (VBL) transferred to the minor loop by the write line transfer gate 4 can move the stripe domain domain wall that constitutes the minor loop.Minor The information transfer from the loop to the major line involves the conversion from VBL to a bubble.This readout transfer gate 5 is a block replicator.In this way, the minor loop is composed of striped domains existing in the bubble material, and the minor VB in place of bubble domain as information unit on loose
By using J-, it is possible to achieve approximately two orders of magnitude improvement in memory R and meat production compared to devices using conventional bubble domains.

The configuration example and operation of this element will be explained in more detail. The major line uses a current drive method for both writing and reading.

A write transfer gate consisting of four parallel conductors uses interaction between a bubble on a major line and a striped domain head forming a minor loop. When there is a bubble domain on the major line line, the heads of the stripe domains that make up the minor loop connected to it take full advantage of moving away from the bubble due to the repulsive interaction between the bubble and the stripe domain. When there is no bubble on the written major line, vBL is applied to the minor loose striped domain domain wall.
klF included. As a means of forming a VBL into a stripe domain head, a pulse current is applied to a conductor pattern in contact with the stripe domain head to dynamically move the head, thereby dynamically converting the head domain wall. This method creates two VBLs, which have different properties and are easy to recombine. Therefore, in order to stabilize the information, an in-plane magnetic field is applied in the longitudinal direction of the striped domain, and the striped domain head is separated by two conductors on the striped domain side. Create a VBL of VBLs with the same properties stably exist even if they approach each other. The minor loose stripe domain head corresponding to the area where the bubble is present on the major line is repelled by the bubble and recedes from the conductor pattern, so no VBL is formed. As a result, the major line information "1" is transferred with no VBL pair in all minor loops.

In the minor loop, information is stored using a pair of VBLs with the same properties as one bit. An eVBL pair is used in consideration of the stability of the replicator action.

Bit period in the minor loop 5. A transfer pattern is set so that one bit can be transferred successively so as to keep the VBL interval constant. - As an example, a stable interval S between VBLs in the direction perpendicular to the longitudinal direction of the striped domains on the striped domains constituting the minor loop. The period is twice that of the width S. A parallel thin line pattern made of permalloy thin film is formed, and magnetic poles and V induced on both sides of the parallel thin line are formed.
It utilizes interaction with BL.

One method for transferring VBL along the minor loose is to dynamically perform it by applying a pulsed bias magnetic field to the stripe domain.

A readout transfer gate consisting of three parallel conductors converts the information stored as VBL in the stripe domain domain wall forming the minor loop into a bubble and transfers it to the major line, and also transfers the information on the minor loop. It also has a replicator function that prevents it from being destroyed.

The operating principle will be explained. One bit formed by a VBL pair is fixed to a stripe domain head by applying an in-plane magnetic field, for example. Then, using the conductor pattern 1. Make this striped domain head completely into a bubble. Then, the striped domain head after removing the bubble will have the same VBL as the VBL when it was removed.
is configured.

Such a VBL replication effect occurs when VBL has a minus sign.

Bubbles taken from the striped domain head of the minor loop are transferred along the major line toward the detector. Here, it is utilized that the value of the pulse current taken through the entire striped domain head is different depending on whether the striped domain head has VBL or not. If there is no VBL on the striped domain head, it will be difficult to cut. Therefore, if the striped domain head has VBL, a bubble can be sent to the major line, but VB
If there is no L, there is no bubble. The presence or absence (1, 0) of VBL on the minor loop is converted to the presence or absence of a bubble on the read major line.

The elimination method for VBL pairs will be described. Place the VBL pair to be erased at the position closest to the minor loose stripe domain head on the writing major line side. Next, the in-plane magnetic field H
In addition to ipi, as soon as it is erased, the VBL pair and its next V
One side of the BL pair was brought to the full stripe domain head, and the parallel conductor was used to cut off the positive VBL'5 when writing information. il history has a striped domain head as a child. After removing the bubble domain, the striped domain head has the V you want to erase.
The VBL brought with the BL pair is replicated.

Eventually, only the VBL pair will be erased as soon as it is erased.

In addition, when clearing the entire minor loop, first erase all the stripe domains by increasing the bias magnetic field, and then form the minor loop drive domain from the S=1 bubble. It is possible to create a state where all the pits are zero and there is no VBL.

The present invention relates to the erasure of vertical Ploch lines used in the above chip.

FIG. 2 shows the previously proposed vertical Ploch line elimination method, in which all vertical Ploch lines are eliminated by the operation described below.

Write the VBL pair you want to erase as shown in Figure 2 (,) and write the VBL pair you want to erase on the minor loose strike on the major line side.
Parallel conductors 8 and 9 were used to bring the BL pair and one half of its VBL pair to the striped domain head and to provide a small VBL with a gap for information writing.
Cut out the striped domain head. After the bubble domain is removed, the VBL that was brought along with the VBL pair you want to delete is replicated in the striped domain head.
Unless one half of the adjacent VBL pair is brought to the stripe domain head at the same time, the VBL pair cannot be erased.

In other words, if there are consecutive VBL pairs as an information string, it can be erased, but if there is a VBL pair next to the VBL pair that you want to erase,
There is a drawback that it cannot be eliminated when L pairs do not exist.

The present invention improves this drawback and allows VBL to be used independently of information strings.
An object of the present invention is to provide a magnetic memory element having the feature that pairs can be erased.

That is, the present invention includes an information reading means, an information writing means, and an information storage means, and is capable of detecting the area around a stripe domain existing in a ferromagnetic film (including a ferrimagnetic film) whose easy magnetization direction is perpendicular to the film surface. A major-minor configuration characterized in that a vertical Ploch line pair consisting of two adjacent vertical Bloch 2-ins formed in a Bloch domain wall is used as a storage information unit, and has a means for transferring the vertical Ploch line within the Bloch domain wall. The present invention is a magnetic memory element characterized in that an in-plane magnetization layer is provided near the end of each minor loose.

Next, the gist of the present invention will be described in detail using the drawings. Third
The figure is a principle diagram showing the VBL pair elimination method according to the present invention. When there is a VBL pair to be erased, by extending the stripe domain, it can be held at the end of the mica loop "31" (FIG. 3(a)). Next, one of the VBL pairs is connected to the in-plane magnetization N (for example, the ion-implanted layer) portion "32".
By applying an in-plane magnetic field Hip'iz to (
Figure 3(b)). Next, when the in-plane magnetic field is removed, the magnetization in VBL in the in-plane magnetization layer is partially reversed due to the stray magnetic field "H" from the striped domain retention layer, and the Bloch point at the boundary between the two is partially reversed. is injected. νl'', the direction of magnetization on the Ploch line is reversed and becomes the same direction as the other VBL pairs left outside the in-plane magnetization layer (
Figure 3 (C)). On the minor lube, the VBL pair with gold magnetization in the same direction approaches each other (Figure 3 (d))
,Join. This erases one VBL pair (
Figure 3(e)).

By providing an in-plane magnetization layer in this way and injecting a Bloch point into one of the VBL pairs upon erasure, the VBL
Since the pair can be erased, there is no need for one half of adjacent bits, which is different from the already proposed example (FIG. 2), and it is possible to erase a desired VBL pair without depending on the information string.

FIG. 4 is a 10★ embodiment according to the present invention.

In this embodiment, an in-plane magnetization layer for Loch point extraction is provided over the entire major line portion. The operating principle is the same as in FIG.

FIG. 5 shows a second embodiment of the present invention, in which the in-plane magnetic layer is provided for each corresponding mica loop portion in all major lines.

In the embodiment of the present invention, an in-plane magnetization layer is provided in the major line portion near the minor loose end, but an in-plane magnetization layer is provided in the mica loop region K or in a position close to the minor loose VBL. Bloch on one side of the pair
It goes without saying that the present invention also includes a case where the point l-' is injected.

Although an ion-implanted layer is shown as the in-plane magnetization layer in the embodiment, a layer in which the surface layer of a bubble retention film or a stripe domain retention film is an in-plane magnetization layer is included in the in-plane magnetization layer of the present invention. Needless to say.

In addition, if you want to clear the entire minor loop, in advance,
After once erasing all the stripe domains by increasing the bias magnetic field, a minor loop drive domain is formed from the pull of S=1, thereby creating a state in which the VBL has no heat and all pits are zero.

[Brief explanation of drawings]

FIG. 1 is an overall diagram of a memory chip using Ploch lines. FIG. 2 is a diagram showing the conventional Ploch line elimination method.
is a generator, 2 is a minor loop, 3 is a bubble, 4 is a write line transfer gate, 5 is a read transfer gate, 8.9.33 is a parallel contact, 10 is a striped domain head, 31 is a minor loop, 32
indicates an in-plane magnetization layer, and 34 indicates a perpendicular Bloch line into which Bloch points are injected. Gi 3 Figure Major 1ine Rod S Mouth 3

Claims (1)

[Claims] Bloch Mik around a stripe domain existing in a ferromagnetic film (including a ferrimagnetic film), which is equipped with an information reading means, an information writing means, and an information storage means, and whose easy magnetization direction is perpendicular to the film surface. A magnetic memory having a Mejiro-minor configuration, characterized in that a vertical Ploch line pair consisting of two adjacent vertical Ploch lines formed inside is used as a storage information location, and has a means for transferring the vertical Ploch line within a Bloch magnet. 1. A magnetic memory element, characterized in that an in-plane magnetization layer is provided near an end of each minor loose.