JPS5998382A - Magnetic storage element - Google Patents

Abstract

PURPOSE:To generate a high-density magnetic storage stripe domain each minor loop with good arrangement by providing a bubble domain generator conductor pattern and a bubble domain transfer pattern. CONSTITUTION:A minor loop region 20 is provided with a hairpin-shaped bubble generator conductor pattern 21 and bubble domain transfer patterns 22, 23 having two-layer opening of periodical arrangement. A bubble domain 24 generated by the pattern 21 is transferred by two-layer opening currents 27, 28 flowing alternately to the patterns 22, 23 perpendicularly to the transfer direction. Further, when the vertical magnetic field is reduced while the planer rotating field is applied unidirectionally, a high-density storage stripe domain 25 taking the vertical Bloch line pair as magnetic storage information is generated on the stripe domain storage pattern 26 of each minor loop with good arrangement.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to stripe domain generation means for a magnetic memory element.

The development of magnetic bubble elements is actively being carried out in various places with the aim of increasing density, including permalloy devices, ion-implanted contiguous disk devices, current m=devices, and so-called hybrid devices that combine these devices.

It has been said that the limit to the high density of these devices lies in the photophosphorographic technology that cannot be used to form bubble transfer paths.

However, in recent years, the technology has advanced rapidly.

As a result, the question of how small the bubble diameter, that is, the material needed to increase the density, has become a problem. With the garnet materials currently in use, the minimum attainable bubble diameter is said to be 0.3 μm. Therefore, it is necessary to find a bubble material other than garnet material that retains zero bubbles with a diameter of 03 μm or less. This is not easy and is even considered to be the limit of bubble density.

On the other hand, as a memory element, it is possible to significantly improve the density limit based on the characteristics of such a bubble retaining layer, and to keep the information read time to the same level as conventional elements. In a magnetic memory element comprising a means and an information storage means, a Bloch domain wall around a stripe domain existing in a ferromagnetic film (including a ferrimagnetic film) whose easy magnetization direction is perpendicular to the return plane. Adjacent 5N made inside! - A magnetic memory element has been conventionally used in which a pair of vertical Bloch lines is used for storage ↑H and has means for transferring the vertical Bloch line within a Bloch domain wall. This element can have both a shift register configuration and a major-minor configuration, but here, one type of vertical Ploch line memory will be described using the major-minor configuration as an example. In this example, the major line uses conventional Shiba pull domains as the information unit, the minor loop consists of stripe domains, and the information unit is the vertical Ploch line (hereinafter referred to as VBL) existing within the Bloch domain wall around the major line. state FIG. 1 is an overall view of the chip. To show the overall flow of information, first, the information written by the generator 1 (the presence or absence of bubbles) moves from the top to the bottom of the writing major line. In order to store this information in minor loop 2, the minor loose is set to VB so that the information on the major line indicated by the presence or absence of bubble 3 can be transferred to the minor loop in VBLQ form.
The feature of the present invention is that it is composed of Bloch domain walls that can hold L, and is an important key to dramatically improving storage capacity. To the write line transfer gate 4,
Information transferred to minor looses (VBL)
It is possible to move the Rustlife domain domain wall soil that constitutes a minor loop. Read from the minor loop to the major line! ! ) Transfer involves converting VBL to a puzzle. Note that this read transfer gate 5 also has a block replicator function.

In this way, by configuring the minor loose with striped domains that exist in the bubble material and using VBL in place of the bubble domain as an information unit on the minor loose, we have achieved an improvement compared to devices using conventional bubble domains. It is possible to achieve an improvement of about two orders of magnitude in memorization.

The configuration example and operation of this element will be explained in more detail. The major line uses a single current mining method for both loading and reading. The advisory transfer gate consisting of four parallel conductors uses the interaction between the bubble on the major line and the striped domain head forming the minor loop. When there is a bubble domain on the major line line, the heads of the stripe domains forming the minor loop connected to it move away from the bubble due to the repulsive interaction between the bubble and the stripe domain. When there is no bubble in the write major line, VBL is convolved with the stripe domain domain wall of the minor loop.

As a means of making VBL into a striped domain head,
Conductor connecting the striped domain head to it
The pattern is dynamically moved by applying a pulse current to dynamically convert 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 stripe domain, and the stripe domain head is separated by two conductors on the stripe domain side. Create a VBL of properties.

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 exists on the major line is separated from the conductor pattern due to the repulsion with the bubble, so no VBL is formed. As a result, information "1" on the major line is transferred with no VBL pair in the minor loop.

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

A transfer pattern is provided to selectively transfer one bit at a time so that the bit period, -tb, and VBL interval within the minor loop are kept constant. - As Ray i, a parallel fine line pattern made of a permalloy thin film with a width Sc is formed on the striped domain constituting the minor loose with a period twice as long as the stable interval S6 between VBL in the direction perpendicular to the longitudinal direction of the striped domain. In addition, the interaction between the magnetic trowel and VBL, which are generated on both chests 1j of parallel thin wires, is utilized.

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 striped 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 functions as a replicator to prevent destruction. The operating principle will be explained. One bit formed by the VBL pair is fixed to the stripe domain head by applying an in-plane magnetic field, for example. .

A conductor pattern is then used to create a bubble between the striped domain head and the cut.

Then, the same VBL as the VBL with the cut portion removed is configured in the stripe domain head after the bubble cut portion is removed. Such a VBL replication effect occurs only for a VBL with a minus sign.

The bubble cut from the minor loose striped domain head is transferred on the major line toward the detector. Here, it is utilized that the value of the pulse current that cuts the 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, striped domain head K V B
If there is L, a bubble can be sent to the major line, but if there is no VBL, 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
Add the ip, the VBL pair you want to delete, and its VBL pair
One half of the BL pair is brought to the stripe domain head, and when writing information, the stripe domain head is cut using the parallel conductor used to cut the positive VBL. After the bubble domain is removed, the VBL that was brought along with the VBL pair to be deleted is replicated in the striped domain head. In the end, only the VBL pair that is desired to be erased will be 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 of pit zero.

In this magnetic memory element, the most fundamental problem in this element is how to generate striped domains that form minor loops. In other words, it is known that irregular labyrinth-like striped domains can exist in normal ferromagnetic simulations without an applied magnetic field, but they can be generated by regularly arranging an arbitrary number of striped domains. Effective means are still not well known.

The present invention is directed to each minor objective of the magnetic memory element.

According to the present invention, a ferromagnetic film (containing a ferrimagnetic material JM) is provided with a jW information reading means, an information borrowing means, and an information storage means, and whose easy magnetization direction is perpendicular to the film surface. A magnetic field with a major-minor configuration that uses a vertical Ploch line pair consisting of two perpendicular Ploch lines that meet each other instantaneously created in a Bloch domain wall around a striped domain as a storage information unit, and has means for transferring the vertical Ploch lines within the Bloch domain wall. A magnetic memory element is obtained in which a bubble domain generator conductor pattern and a periodic bubble domain transfer pattern are provided in a minor loose region constituted by striped domains.

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

Embodiment 1 FIG. 2 is a schematic diagram showing an embodiment of the configuration of a minor loop region of a magnetic memory element of the present invention. FIG. 2 partially shows the minor loop region of FIG. Second
In the figure, a hairpin-shaped conductor 21 is formed in a part of the minor loop region 20, and then a two-layer conductor open loop pattern 2 is formed.
The feature of this embodiment is that 2.23 is formed. A bubble 24 is generated using the conductor pattern 21 under a constant vertical bias magnetic field, and then a two-layer conductor pattern 22 .
The shiva pull 24 is transferred to each minor loop position by the current drive method of 23. That is, bubbles are transferred by alternately flowing two-layer conductor sleep currents 27 and 28 in a direction perpendicular to the transfer direction. After that, when the perpendicular bias magnetic field is decreased while applying the in-plane magnetic field in one direction, the stripe domain 25
You will get a column of The pattern 26 is a soft magnetic material pattern or a metal pattern for holding the striped domain at a constant length in one direction. Note that even without the pattern 26, it is possible to align the stripe domains to some extent by controlling the in-plane magnetic field.

Embodiment 2 FIG. 3 is a schematic diagram showing another embodiment using a two-layer conductor transfer pattern similar to the Ml embodiment.

The difference from the first embodiment is that the stain flow consumption is reduced by changing the arrangement of the open rubber patterns 22 and 23 and providing striped two-layer conductors 22' and 23' instead of a full-surface two-layer conductor. It is. In the case of this embodiment, the two-layer conductor current 27, 2
8, the flow is parallel to the bubble traveling direction.

In this case as well, striped domains can be generated regularly as in the embodiment.

Embodiment 3 FIG. 4 is a schematic diagram showing another practical example of the present invention. In this embodiment, a hairpin conductor pattern 21 using the magnetic field of a permalloy pattern 41 as a ridge bubble generator,
A feature is that a permalloy pattern 42 is provided on the bubble transfer pattern.

After transferring the bubble 24, striped domains 25 are formed using an in-plane applied magnetic field and a permalloy striped domain holding pattern 26.

Embodiment 4 FIG. 5 is a schematic diagram showing another embodiment of the present invention. This embodiment is characterized in that the bubble transfer pattern is provided using ion implantation. In FIG. 5, transfer pattern 51 represents a non-ion implantation pattern of the bubble retention layer. Here, a hairpin-shaped conductor magnetic bubble generator 21 generates a hairline bubble at the end of the shiba turn 51, and the bubble 24 is transferred along the pattern 51. The bubbles in the ion-implanted region can easily form the stripe domain 25 by using the characteristic that the bubbles in the ion-implanted region are easily elongated by applying an in-plane magnetic field in the direction of difficult magnetization of the ion-implanted layer. Pattern 52 is a striped domain retention pattern. Here, pattern 52 is a non-ion implantation pattern. In this case as well, regularly aligned striped domains are obtained.

As explained above, according to the present invention, a means for generating stripe domains in each minor loop row can be obtained, which is useful for realizing a large-capacity magnetic memory element in which a VBL pair on a stripe domain is a unit of storage information. Great effect. Furthermore, it is easily inferred that the stripe domain generation means of the present invention can be applied to the case where Bloch points are used as storage information units for the VBL of a stripe domain.

[Brief explanation of the drawing]

Figure 1 shows VBL pairs on a striped domain.
Bubble generator, 2--minor loop, 3--bubble, 4--containment transfer gate, 5-- readout transfer gate, 20-- minor loop region, 21-- bubble generator conductor pattern, 22 .23...
・Two-layer conductor open pattern, 24... bubble domain,
25-stripe domain, 26... stripe domain retention pattern, 27.28... two-layer conductor current, 2
2', 23'... Two-layer conductor, 41... Permalloy pattern, 42... Permalloy transfer pattern, 51...
- Non-ion implantation transfer pattern, 52... Stripe domain holding non-ion implantation pattern. O 1 Roa 2 Kasai 5 Ro is 〆121? l/-Figure O, 5 FA

Claims (1)

[Claims] A bloch around a stripe domain existing in a ferromagnetic film (including a ferrimagnetic film) that includes an information reading means, an information convolution means, and an information storage means and whose easy magnetization direction is perpendicular to the film surface. In a magnetic storage element with a major-minor configuration, a vertical Proch line pair consisting of two adjacent vertical Proch lines formed in a domain wall is used as a storage information unit, and the vertical Proch line is transferred within the Bloch domain wall. 1. A magnetic memory element characterized in that a bubble domain generator conductor pattern and a periodic bubble domain transfer pattern are provided in a minor loose region.