JPS5824863B2 - Cylindrical domain element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cylindrical magnetic domain element including a magnetic memory element using a cylindrical magnetic domain.

More specifically, the present invention relates to a cylindrical magnetic domain element in which when transferring a cylindrical magnetic domain using an in-plane rotating magnetic field, the difficulty of transferring the cylindrical magnetic domain differs depending on the rotation direction of the in-plane rotating magnetic field.

Volume 6 of the Bell System Technical Journal, published in 1967, pages 1901 to 1925.
ourna 1, Vol, 46, 1901-192
Since the possibility of devices using cylindrical magnetic domains was announced by A.H. Bobeck in 5, pp.

It is common to use an array of soft magnetic thin film batons and an in-plane rotating magnetic field as described in US Pat. No. 3,540,019 by Bobeck et al.

As can be seen in the above-mentioned US patent, the shape of the cylindrical domain transfer button is well symmetrical, as represented by the T-shape, and can move in either direction with respect to the arrangement of the button rows, depending on the rotational direction of the in-plane magnetic field. Cylindrical domains are similarly transferred.

The configuration of a cylindrical domain element using such a cylindrical domain transfer pattern was published in 1970 in IE Transactions on Magnetics, Volume 6, No. 3 (September issue) for file memory. ) pages 447 to 45
Page 1 (IEEE Trans.

MagnlMag-6(A3) pp 447-4
51 (Sept1970)], 1. Bonyh
The most common method is the major-minor loop method announced by Ard et al.

Initially, rare earth orthoferrite was used as a piece of magnetic material for holding cylindrical magnetic domains, but the use of garnet material to increase the density of stored information was proposed by A. H. Bobeck in 1970 in U.S. Patent No. 3,646,529. Ta.

In a major-minor loop type cylindrical magnetic domain element using a garnet material, unnecessary cylindrical magnetic domains are likely to be generated within the element during high-speed transfer of cylindrical magnetic domains, which causes malfunction of the element.

To prevent this, a guard rail made of T-shaped or T-shaped permalloy thin film transfer tabs is provided around the device, as disclosed in US Pat. No. 38 by A. H. Bobeck, for example.
10132, P-I, 1 by Bonyhard
973 I.E., Transactions on Magnetics, Volume 9, No. 3, pp. 433-436 (IEEE Trans.

Magn, Mag-9 (Haruka 3) pp, 433
~436 (1973)).

On the other hand, in a major/minor type cylindrical domain element that is accessed using an in-plane rotating magnetic field, by reversing the direction of rotation of the in-plane magnetic field depending on the position of the stored information, the stored information in the minor loop is averaged. It is known that it can be accessed twice as fast.

In such cases, in the guardrail using the conventional transfer pattern described above, due to the symmetry of its constituent pattern and the symmetry with respect to the transfer of cylindrical magnetic domains, unnecessary cylindrical magnetic domains outside the element operating area are moved into the element operating area. As a result, they are unable to fulfill their role.

Also, the above cited paper (IEEE Trans-Magn,
, Mag-9 (A3) pp 433-436 (19
In the major/minor type cylindrical domain element accessed by an in-plane rotating magnetic field using a conventional cylindrical domain transfer pattern, which has been treated in・It is provided in only one place in the loop, and when erasing a large amount of information, all the cylindrical magnetic domains to be erased must be transferred to the same eraser, resulting in a huge loss of time. Hey.

In order to eliminate the above-mentioned drawbacks, the present invention allows transfer in any one direction of rotation of the cylindrical magnetic domain, that is, only one transfer direction of the cylindrical magnetic domain, depending on whether the transfer direction of the cylindrical magnetic domain is forward or reverse with respect to the rotation direction of the in-plane rotating magnetic field. A cylindrical magnetic domain element having a cylindrical magnetic domain transfer pattern is provided.

The cylindrical magnetic domain element according to the present invention includes a piece of magnetic material capable of holding a cylindrical magnetic domain (hereinafter simply abbreviated as cylindrical magnetic domain material), and a bias static magnetic field generator for making the cylindrical magnetic domain stably exist in the cylindrical magnetic domain material. a magnetic domain circuit including a magnetic domain circuit, a circuit including a cylindrical magnetic domain generating element that arbitrarily generates a cylindrical magnetic domain in a cylindrical magnetic domain material, a detection circuit including a detecting element for detecting a cylindrical magnetic domain, an arranged soft magnetic pattern for cylindrical magnetic domain transfer, and a shape A pattern having a predetermined number of pieces that is asymmetrical with respect to the mirror symmetry plane perpendicular to the cylindrical domain transfer direction (hereinafter abbreviated as an asymmetric pattern)
and an in-plane rotating magnetic field control means that controls and magnetizes the transfer pattern.

Next, the present invention will be explained in detail using the drawings.

FIG. 1 is a diagram for explaining the present invention in detail using a T-shaped--shaped pattern which is a typical example of a cylindrical magnetic domain transfer pattern.

In the case of the present invention, the ■-shaped pattern 1 and the T-shaped patterns 2 and 3 are made of a soft magnetic thin film such as permalloy, and are provided on the surface of a thin piece of cylindrical magnetic domain material either in close contact or with a nonmagnetic layer interposed therebetween.

The transfer of cylindrical domains by these T-type-I chant magnetic patterns is described in U.S. Patent No. 35 by A. H. Bobeck et al.
No. 40019 provides a detailed explanation.

A feature of the present invention is that an asymmetric pattern is provided in the conventional transfer pattern arrangement.

An example of an asymmetric pattern is a pattern in which a recess 5 in the magnetic material or cylindrical domain material exists at an asymmetric position in the pattern, or a partial omission 6 at an asymmetric position in the transfer pattern.

Furthermore, it goes without saying that the present invention also includes a case where the transfer pattern itself is asymmetric, as shown in 4, for example.

Hereinafter, for convenience, the portion that causes asymmetry due to its existence will be referred to as a magnetically non-homogeneous portion.

When a cylindrical magnetic domain is transferred using such an asymmetric T-shaped -■-shaped pattern, the cylindrical magnetic domain is extremely transferred in the cylindrical domain transfer direction 7 corresponding to the rotation in the direction of the arrow 71 of the in-plane rotating magnetic field HR9. In contrast to the cylindrical domain transfer direction 8 which is easy to transfer and corresponds to the reverse rotation direction 81, the cylindrical domain is very difficult to transfer.

Generally, a magnetically non-homogeneous portion obstructs the passage of a cylindrical magnetic domain, but the degree of inhibition differs due to the asymmetry of its location.

If the transfer of the cylindrical domain is inhibited by such a magnetically inhomogeneous part 5 or 6, the cylindrical domain will be more stable if it moves towards the magnetic poles of the pattern closer to the inhomogeneous part than if it moves further away. It is clear that

Therefore, when the cylindrical magnetic domain is transferred in the direction of arrow 7, the bias magnetic field margin for transfer is wider than in the case of arrow 8.
In the predetermined bias magnetic field range, the direction of arrow 8 is no longer allowed as the transfer direction of the cylindrical magnetic domain, and the cylindrical magnetic domain disappears in that area.

Let me give a concrete example below. (YEuYb)s(FeGa
) A cylindrical magnetic domain material of mixed rare earth iron gallium garnet having a general composition of
A T-type-I-type permalloy pattern is provided, and a 1 μm magnetic non-homogeneous portion is placed at an asymmetrical position as shown in Figure 1a.
When a pit-like depression about the size of the diameter is placed on the crystal, the bias magnetic field margin for the transfer of the cylindrical magnetic domain in the direction of arrow 7 is about 90% compared to when there is no non-homogeneous portion, and for the transfer in the direction of arrow 8. It is about 1%.

The difference is huge. What limits the margin is the decrease in the extinction bias magnetic field value of the cylindrical domain during transfer.

When a permalloy dot with a diameter of about 1.5 μm is provided as a magnetically non-homogeneous part at a position as shown by 5 in Figure 1a, the bias margin of the transfer of the cylindrical magnetic domain in the direction of arrow 7 is equal to the non-homogeneous part. However, the bias margin for cylindrical domain transfer in the direction of arrow 8 is only about 80%.

The magnetically non-homogeneous portion 6 shown in FIG. 1 is a cut portion of a cylindrical domain transfer button.

When a hole with a diameter of approximately 2 μm is provided approximately 5 μm inside the tip of the T-button, the cylindrical magnetic domain transfer margin is 100% for transfer in the direction of arrow 7 and approximately 70% for transfer in the direction of arrow 8. It is.

The example shown in FIG. 1C is a special case of the example shown in FIG.

In either case, the transfer margin is limited by the reduction in the bias magnetic field value at which the transfer cylindrical magnetic domain disappears.

Therefore, in a bias magnetic field region that is larger than the upper limit of the narrow transfer margin and smaller than the upper limit of the wide transfer margin, only one-sided transfer of the cylindrical magnetic domain is possible.

In the present invention, using the above-mentioned principle, in a predetermined bias magnetic field range, by providing a transfer bump that is asymmetrical with respect to a plane of mirror symmetry perpendicular to the cylindrical domain transfer direction, substantially one direction is achieved. Therefore, it is possible to provide a transferable cylindrical magnetic domain transfer pattern.

Next, an embodiment of the present invention will be described with reference to the drawings. Fig. 2 is a conceptual diagram showing the configuration of an embodiment of the present invention.

An array of soft magnetic film patterns (hereinafter abbreviated as transfer patterns) 28 for transferring cylindrical magnetic domains is provided on the cylindrical magnetic domain material 21 via a nonmagnetic layer 22 such as 5jO2.Al2O3.

An asymmetrical button portion 24, which is a feature of the present invention, is provided in any part of this transfer pattern.

It goes without saying that the asymmetrical button portion 24 may be constructed simultaneously with the transfer pattern 23.

A cylindrical domain generator and eraser 25 is constructed simultaneously with the transfer pattern 23 and is connected to an external control circuit 251 in a mutually coupled relationship 28.

The transfer button section 23 is placed in a position related to the in-plane rotating magnetic field generating means 26 for driving the cylindrical magnetic domain and the control means 261 thereof.

Further, a bias static magnetic field generator 27 for stably existing the cylindrical magnetic domain and its control means 271 are integrated to form the present cylindrical magnetic domain element.

FIG. 3 is a diagram for explaining the first embodiment of the present invention.
The drawing is drawn with particular attention to the magnetically non-homogeneous portions that give asymmetry to the transfer pattern and battens in FIG.

A magnetically non-homogeneous portion 30 represented by FIG. 1a is provided in the T-shaped--shaped transfer button array 31 as shown in the figure.

Based on the principle of the present invention described above, in a predetermined bias magnetic field range, the rotational direction 33 of the in-plane magnetic field for driving the cylindrical magnetic domain
1, the cylindrical magnetic domain is transferred in the direction of the arrow 33, but not in the opposite direction due to the presence of the non-homogeneous portion 30.

Similarly, with respect to the reverse rotation direction 321 of the in-plane magnetic field, the transfer direction of the cylindrical magnetic domain is the direction of the arrow 32.

In other words, for any direction of rotation of the in-plane magnetic field, the cylindrical magnetic domain is transferred only in the directions indicated by arrows 32 and 33.

Therefore, using the button row shown in this example as a guardrail, the cylindrical magnetic domain memory operating portion is
If placed on the 0 side, it will operate as a guardrail for any in-plane magnetic field rotation direction.

That is, by using this embodiment, it is possible to easily realize a cylindrical magnetic domain element that can be rotated in forward and reverse directions and that can substantially shorten the access time.

FIG. 4 is a diagram for explaining the second embodiment of the present invention,
A case will be explained in which the loop-shaped cylindrical magnetic domain transfer button 44 is composed of a T-shaped-■-shaped pattern row 43.

When the magnetically inhomogeneous portion 40 is in the position represented in FIG. 4, within the range of a predetermined bias magnetic field, the cylindrical magnetic domain is transferred only in the direction of the arrow 42, and in the opposite direction 41, the cylindrical magnetic domain is transferred. Disappear.

Therefore, if we use an asymmetric batten array with such non-homogeneous parts in the minor loop part of a cylindrical magnetic domain element with a conventional major-minor loop structure, it is difficult to erase the cylindrical magnetic domains in all minor loops. It is only necessary to rotate the internally rotating magnetic field once or several times in the opposite direction, and the speed is much greater than the conventional method in which cylindrical magnetic domains are taken out once in a major loop and erased one after another in the major loop.

This elimination method may also be applied to major loops.

This is one of the important effects when implementing the present invention.

Up until now, in the explanation of the principle and the examples, only the T-type-I-type pattern has been described as the transfer button, but the Y-
Of course, the same effect can be obtained by using an asymmetrical baton that is created by providing a magnetically non-homogeneous part at an asymmetrical position, as long as it has a good symmetry, such as a Y-type, Y-I-type, or Chabron-type batten. It is.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the present invention in detail, 1.2,
3 and 4 are cylindrical magnetic domain transfer batons, 4 is an asymmetrical baton that has a magnetically non-homogeneous part within itself, 5 is a magnetically non-homogeneous part outside the baton that imparts asymmetry to the baton, 6
7 and 8 are arrows indicating the cylindrical domain transfer direction corresponding to the rotation directions 71 and 81 of the in-plane magnetic field 90, respectively. FIG. 2 is a conceptual diagram showing the configuration of an embodiment of the present invention, in which 21 is a cylindrical magnetic domain material, 22 is a non-magnetic layer, 23 is a cylindrical domain transfer button, and 24 is a characteristic of the present invention in which asymmetry is imparted to the button. 25 is a cylindrical magnetic domain generator and eraser, 26 is an in-plane rotating magnetic field generating means, 27 is a bias magnetic field generator, 251 is a cylindrical magnetic domain generation detection circuit, 2
61 is an in-plane rotating magnetic field control means, 271 is a bias magnetic field magnetic circuit, and 29 is a main control circuit. FIG. 3 is a diagram for explaining the first embodiment of the present invention,
30 is a magnetically inhomogeneous part that gives asymmetry to the baton;
31 is a cylindrical magnetic domain transfer button, and 32 and 33 are cylindrical magnetic domain transfer paths corresponding to the in-plane magnetic field rotation directions 321 and 331, respectively, and arrows indicating the transfer directions. FIG. 4 is a diagram for explaining the second embodiment of the present invention,
40 is a magnetically inhomogeneous part that gives asymmetry to the baton;
Reference numeral 41 indicates an arrow indicating a direction in which cylindrical magnetic domains are difficult to transfer, 42 indicates an arrow indicating a direction in which cylindrical magnetic domains are likely to be transferred, 43 indicates a transfer button row, and 44 indicates a cylindrical domain transfer path.

Claims (1)

[Claims] 1. A magnetic material capable of holding a cylindrical magnetic domain, a magnetic circuit that allows the cylindrical magnetic domain to stably exist in the magnetic material, a cylindrical magnetic domain generation circuit that causes the magnetic material to generate a cylindrical magnetic domain, and a detection circuit that detects the cylindrical magnetic domain. , an in-plane rotating magnetic field generation control means for transferring the cylindrical magnetic domain, and a predetermined number of bangs whose shape is asymmetrical with respect to a plane of mirror symmetry perpendicular to the cylindrical magnetic domain transfer direction, substantially moving the cylindrical magnetic domain in one direction. A cylindrical magnetic domain element consisting of a cylindrical magnetic domain transfer circuit with a soft-magnetic button array including a transfer button that only transfers the magnetic domain.