JPS5998385A - Write transfer gate - Google Patents

Abstract

PURPOSE:To attain stable writing by constituting a transfer gate for major/ minor loops taking a vertical Bloch line pair as storage information with conductor patterns and a soft magnetic substance film and the like. CONSTITUTION:The write transfer gate of the vertical Bloch line pair of high- density storage is constituted by the soft magnetic substance film 36 between four parallel conductor patterns 31-34 and the stripe domain 35 forming major/ minor lines. Since the tip position of the domain 35 is positioned stably by the film 36 clearly, the writing of information is attained stably without malfunction.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to vertical protrusions that statically and stably exist within Bloch domain walls that form the boundaries of striped domains formed in soft magnetic thin films whose easy magnetization direction is perpendicular to the film surface. The present invention relates to a magnetic memory element using acupoint lines as a memory unit, and more particularly to a write transfer gate portion in the element.

The development of magnetic bubble elements is actively being carried out in various places with the aim of increasing density and speed, including permalloy devices, ion-implanted continuous disk devices, current-driven 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 photolithography technology used to form the bubble transfer path. 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 trivial, and is even considered to be the limit of bubble density.

The present invention proposes a memory element that can significantly improve the density limit based on the characteristics of the bubble retaining layer and that can maintain information read time at the same level as conventional elements.

FIG. 1 is an overall view of this device. To show the overall flow of information, first, the information @ (presence or absence of bubbles) written by the generator 1 moves from the top to the bottom of the writing major line. In order to store this information in minor loop 2, in order to transfer the information on the major line indicated by the presence or absence of bubble 3 to the minor loop in the form of a vertical Bloch line (VBL), the minor loop can be transferred to a bloch that can hold VBL. Consists of domain walls. The information (VBL) transferred to the minor loose by the write line transfer gate 4 can move the striped domain domain wall that constitutes the minor loose. Information transfer from the minor loop to the read major line involves conversion from VBL to bubble. Note that this read transfer gate 5 also has a block replicator function.

In this way, by configuring the minor loop with striped domains existing in the bubble material and using VBL in place of the bubble domain as the information unit on the minor loop, it is possible to improve the structure compared to devices using conventional bubble domains. It is possible to achieve a storage density improvement of approximately two orders of magnitude.

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 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 convolution major line, write a minor loose stripe domain domain wall KVBL.

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 pulsed 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 reduce the information cost, we applied an in-plane magnetic field in the longitudinal direction of the striped domain and separated the striped domain head 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 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 III of 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. Considering the stability of the replicator action (9VBL pairs are used).

A transfer pattern is set so that the bit period in the minor loop, that is, the VBL interval, can be kept constant and selective transfer can be performed one bit at a time. - As an example, a parallel fine line pattern made of a permalloy thin film with a width So is formed on the striped domain constituting the minor loose in the direction perpendicular to the longitudinal direction of the striped domain, with a period twice as long as the stable interval So between the VBLs. , the magnetic poles induced on both sides of the parallel wire and V
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 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 loose. It also functions as a replicator to prevent destruction. The operating principle will be explained.

For example, a 1-bit half formed by a VBL pair is fixed to a stripe domain head by applying an in-plane magnetic field. A conductor pattern is then used to make this striped domain head into a small bubble. Then,
After the bubble is removed, the same VBL as the removed VBL is configured in the striped domain head. This stronger VBL replication effect occurs only for VBLs 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 pulse current value that drives 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, 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 you want to erase in a position closest to the minor loose stripe domain head on the 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 striped domain head, and the striped domain head is removed using the same parallel conductor used to remove the positive VBL when writing information. After the bubble domain is removed, the VBL that was brought along with the VBL pair to be deleted is replicated to 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 fill in the minor loop drive domain from the S=1 bubble, which will be explained in more detail using the drawings. The transfer gate illustrated here uses the interaction between the bubble on the major line and the striped domain head that constitutes the minor loop.

Tsumashi, if there is a bubble domain on the major line,
The head of the striped domain, which constitutes the minor loop connected to it, takes advantage of the fact that it moves away from the bubble due to the repulsive interaction between the bubble and the striped domain.

FIG. 2 shows the operating procedure of a so-called complementary transfer gate that inserts VBL into a minor loose stripe domain domain wall when there is no bubble in the write major line. The transfer gate is made up of four parallel conductors.

If there is no bubble on the major line, the striped domain that makes up the minor loop should be made cheap at the position shown in Figure 2 (al).
As a method for creating L, here, a method is used in which a pulse current Ipl is applied to the conductor line 6 and the striped domain head is dynamically moved in the direction shown in FIG. 2(b). By doing this, the magnetization of the Bloch domain wall part of the stripe head part 10 is rotated by 180 degrees, and the second
The orientation changes from the orientation shown in FIG. 2(a) to the orientation shown in FIG. 2(b). This is called dynamic conversion of domain wall structure. By doing this, on both sides of the striped domain head, there are places where the magnetization of the Bloch domain walls collide with each other11.1
2 can be done. That part is called VBL. If you create a VBL using the method I just described, you will definitely get ■VBL
II and (9VBL12 are paired. ■VBL and □
By placing the VBLs adjacent to each other and applying the internal magnetic field Hip, the Bloch domain wall magnetization of the stripe domain head portion is fixed in the Hip direction, thereby preventing recombination of the eVBLs. However, in actual devices, Hip
It turns out that it is inappropriate to add this from the viewpoint of stability of VBL information. Therefore, here Hip
In order to stabilize VBL information even without VBLO
We devised a way to limit the number of types to one. At that time, we decided to leave 9VBL in consideration of the readout line transfer gate having a resilicator function.Next, we will describe a method of leaving only □VBL in the minor loose stripe domain domain wall. Hip is added in the direction shown in the figure (dl). Then, Zeeman energy is obtained by directing Bloch domain wall magnetization in the Hip direction, so eVBL comes to the stripe domain head. In this state, conductors 8 and 9 are directed oppositely to each other. A pulse current is applied to the stripe domain head to separate it as shown in FIG. 2. Then, a QVBL 13 is formed on the stripe domain head from which the eVBL has been removed.

I left this eVBL and minor loose (9VB
A total of two 19VBLs of L12 are paired to form a bit. Through this series of operations, the information "0°" on the written major line could be transferred into the minor loop as eVBL pair 14.VBLs of the same sign stably exist even if they approach each other.There is no bubble on the major line. If the minor loose striped domain head corresponding to the existing position is placed on the right side of conductor 9 using repulsive interaction with the bubble, the striped domain head will be located on the right side of conductor 9 in the series of operations shown in Figure 2. The head state remains unchanged. Therefore, as a result, the major line information "1°" is transferred as a state in which there is no VBL pair in the minor loop. Incidentally, as shown in Fig. 2+f), the unnecessary bubbles removed by the transfer gate are moved to the major line by applying parallel pulse currents to the conductors 6 and 8, and finally erased.

In this way, when transferring information from the major loop to the minor loop, in the dipping transfer gate, the tip of the minor loose stripe domain is connected to the conductor pattern.
7°, and the position of the tip of the sistripe domain needs to change depending on the presence or absence of a bubble. It is an object of the present invention to provide a more effective write transfer gate having such functionality.

The present invention provides a write transfer gate consisting of a soft magnetic thin film and a plurality of conductor patterns disposed between a major line and each minor loop in a magnetic memory element in which the above-mentioned VBL pair is a unit of stored information. Provided is a transfer gate that can perform stable writing by moving striped domains using a magnetic field and controlling the position of the tip of the striped domains.

The gist of the present invention will be explained in detail using the drawings.

FIG. 3 shows a first embodiment of the present invention. Vertical Ploch line writing conductor “32” and minor loop °3
A soft magnetic film 36" is placed between the 5" and 5" to form a write transfer gate. The operation of the fj-inclusive transfer gate according to the present invention will be explained using FIGS. 4(a) to 4(f).

At ta+ in FIG. 4, the input information string "37" is transferred to the major line to the minor loose position. The bubble ``371'' is stopped at each minor loose position. In Fig. 4(b), the bubble 1371 is connected to the soft magnetic material pattern ``36'' from the major line using the conductor ``32''.
Move it to one end of 1. The bubble °37" that has moved to one end of the soft magnetic material pattern is stably held at one end by interaction with the soft magnetic material pattern °36'. In this state, the stripe domain °35" is a minor loose held in a stable position.

In FIG. 4(c), an in-plane magnetic field "Hin" is applied to magnetize the soft magnetic material pattern "36", and this magnetized magnetic pole stretches the sistripe domain and holds it at one end of the soft magnetic material pattern. Ru. At this time, there is a bubble "37°" at one end.
In the minor loop, the tip 35' of the cisstripe domain extends only halfway due to the counterstripe force. On the other hand, in a minor loop without bubbles, there is nothing to disturb the striped domain, so the striped domain 3
5" is extended to the tip of the soft magnetic material pattern and held. Under this state, a current is applied to the conductor pattern "32", and the vertical Ploch line ( VBL) to the striped "main". Then, move the tip position of the striped domain with the striped pull to the conductor pattern °33" and '34° to the right side (minor loop side) of the conductor pattern °34°. Figure 4 (d) ) shows this state.Next, a current is applied to the conductor pattern 133.''341 to cut the stripe domain, and the stripe domain is cut.As a result of the operation so far, the information string of the Shibadger line is changed to the vertical Ploch line in a minor loose manner. It is written whether or not it exists.

This state is shown in FIG. 4(e). Next, the remaining bubbles in Figure 4(e) are replaced with conductive patterns "32" and '33.
An erase pulse is applied to erase the bubble. Then, by applying an in-plane magnetic field in the opposite direction, the tip of the stripe domain of the minor loop is moved to a stable position of the minor loop, and the information writing operation is completed.

This state is shown in FIG. 4(f).

As described above, according to the present invention, by arranging a soft magnetic material pattern between the major line and the minor loop and training the in-plane magnetic field, the tip position of the stripe domain can be clearly and stably displayed, and therefore information can be written. can be performed stably.

FIG. 5 shows a second embodiment of the invention. Conductor pattern @
41 (31)'' into a hairpin shape and partially overlapped with a soft magnetic pattern, the movement of the bubble and the positioning of the tip of the striped domain were stabilized.

Although the shape of the soft magnetic material pattern in the embodiment of the present invention is rectangular, it goes without saying that shapes other than rectangles are also included in the present invention.

FIG. 3 is a diagram illustrating the principle of operation of the write transfer gate. FIG. 3 is a structural diagram of the first embodiment of the write transfer gate according to the present invention. FIGS. 4(a) to (f) show operation states of the first embodiment 1...Bubble generator, 2...Minor loop, 3...Bubble, 4
...Write line transfer gate, 6.7,8
．． 9... Conductor'-hattern, 10... Stripe head portion, If, 12, 13.14... Bloch domain wall, 31, 32, 33, 34... Conductor pattern, 3
5...stripe domain, 36-...soft magnetic film, 3
7...Bubble, 35', 35''...Stripe domain, 41...Sakai body pattern 2nd mouth Major 1ine 3rd major line Figure 4 (0) Figure 4 (b) 01 0 etc. ) , :lL+ Figure 4 (C) Figure 4 (e) 31 32 3:5 34 Medium Y-fin

Claims (1)

[Claims] The Bloch domain wall around the stripe domain existing in a ferromagnetic film (including a ferrimagnetic film) having an easy magnetization direction perpendicular to the film surface is equipped with an information reading means, an information writing means, and an information storage means. A vertical Ploch line pair consisting of two adjacent vertical Ploch lines formed inside is used as a storage information unit, and a magnetic storage element having a major-minor configuration is formed, which is characterized by having means for transferring the vertical Ploch line within a Bloch domain wall. 1. A write transfer gate comprising a plurality of conductor patterns, and further comprising a soft magnetic thin film disposed between a major line and each minor loop.