JPH0283890A - Method for driving magnetic storing element - Google Patents

Abstract

PURPOSE:To execute the high density with eliminating the limit on the lithography technology on a thin line group formation for element bit position formation by driving an element with plural Bloch line pairs as a unit. CONSTITUTION:A transfer unit setting band 5 by the ion implantation arranged at an interval 1mum is used and a block line (BL) pair up to maximum two pairs is transferred. Namely, in units of the transfer, the BL pairs can obtain three conditions 2, 3 and 4 from 0 to two pairs. At a storing element, they are stored as the data coded by the number of the BL lines to exist at a transfer unit. In order to write plural BLs, the writing process of a pair of BL lines is repeated. The transfer is executed by a bias pulse magnetic field in the same way as the conventional one. An information reading action extends a transfer path edge, moves it to a domain edge to extend the BL pair by the in-plane magnetic field and the domain edge is cut by a hair pin conductor. The cut domain is driven and read by a bias magnetic field slope.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a nonvolatile ultra-high density magnetic memory element.

(Problems to be Solved by the Prior Art and the Invention) Magnetic bubble elements are being actively developed in various places as a substitute for high-density solid-state magnetic storage elements. However, with the currently used garnet materials, the minimum attainable bubble diameter is 0.
It is said to be 3pm. Therefore, a bubble material that retains bubbles with a diameter of 0.3 pm or less must be found other than garnet material. This is not easy and is even considered to be the limit of bubble density. We have developed an ultra-high-density magnetic memory element that is magnetized in the direction perpendicular to the film surface, which can significantly improve the high-density limit based on the characteristics of the bubble retention layer, and keep the information readout time at the same level as conventional elements. Vertical Bloch lines (hereinafter simply referred to as Bloch lines) exist statically and stably within Bloch domain walls that form the boundaries of striped domains formed in soft ferromagnetic (including ferrimagnetic) films with easy directions. )
A device using a pair of brosopor lines as a memory unit was developed (Japanese Patent Application No. 182346/1983).

One of the most important parts of this device is the transfer of the VBL pair that carries information.

In principle, for selective transfer of one bit at a time, means is required to apply a force to drive the VBL pair along the domain wall. In reality, a method of applying a local in-plane magnetic field in the form of a traveling wave along the domain wall surface to the VBL pair existence region, and a method of applying a pulse bias magnetic field to the stripe domain domain wall to dynamically move the domain wall and thereby causing the VBL pair to change. It has been considered to utilize gyroscopic force, which is one of the reactions caused by position, but the former can only be achieved by using a conductor pattern, and four conductors are required to form one bit. However, this is not practical when aiming to increase the density and capacity of devices. On the other hand, in the latter case, in order to form one bit, it is sufficient to form a pattern using a single metal, magnetic material, or ion implantation, but this still increases the element capacitance and makes it difficult to compare with current drive. Similarly, the limits of phosphorography technology in the device manufacturing process are approaching, making it difficult to increase the density in practice.

An object of the present invention is to eliminate such conventional problems, to avoid the limitations of phosphorography technology in forming thin line groups for forming element bit positions, and to provide an ultra-high density magnetic memory element. be.

(Means for Solving the Problems) That is, the present invention has information reading means, information writing means, and information storage means, and uses a ferromagnetic material (phenomagnetic material) whose easy magnetization direction is perpendicular to the film surface. The device has means for driving a pair of vertical pro-novo lines, which are formed in the Bloch domain wall at the boundary of striped domains in the film (including the structure), and which consists of two adjacent vertical Bloch lines, within the Bloch domain wall. This is a method for driving a magnetic memory element, characterized in that the elements are driven in pairs.

(Embodiment) An object of the present invention is to provide a high-density magnetic memory element using Bloch lines as information carriers, which is not subject to restrictions on lithography technology in the element manufacturing process, by adopting the above-described configuration. Hereinafter, a detailed explanation of a configuration example of the present invention will be given.

FIG. 1 shows the state of Bloch line pair transfer in the present invention. In this embodiment, a transfer unit setting pattern 5 by ion implantation arranged at an interval of 1 pm is used, and a maximum of 2
It is configured to transfer Bloch line pairs up to the pair. That is, three states 2.3.4 are possible in which the number of Bloch line pairs ranges from zero to two in this transfer unit. In the storage element of the present invention, a pair of Bloch lines directly corresponds to one bit, and data is stored as coded data according to the number of Bloch lines existing in a transfer unit. Therefore,
The bit density in one direction of the transfer path is calculated to be 1.5 bits/pm. On the other hand, in the conventional example shown in FIG. 2, a pair of Bloch lines exist in the pattern formed by ion implantation at intervals of 111 m, which is the same transfer unit as in the present invention, and this corresponds to one hit, and the bit density in the direction of the transfer path is 1 bit/bit. It is pm. As described above, this embodiment has a storage density 1.5 times that of the conventional example. 6 in the figure is an in-plane magnetic field.

In addition, in the case of a configuration in which up to three Bloch line pairs can exist between transfer units, the storage density is 2 bits 111 m, and in the case of a configuration in which up to four Bloch line pairs can exist, the storage density is 2.
The rate increases to 25 bits/pm. As the number of Bloch line pairs that can exist in a transfer unit constituted by such an ion implantation pattern array increases, the storage density also increases, but the degree of increase becomes smaller.

The write operation of the Bloch line pair in the magnetic memory element of this method is performed in the same manner as in the conventional example. By elongating the domain at the end of the transfer path and applying an in-plane magnetic field to generate horizontal Bloch lines, and further applying a pulsed magnetic field in the direction of the bias magnetic field, the horizontal Bloch line is punched through and the elongated domain is cut. By doing so, a pair of Bloch lines can be written. This process can be repeated to write multiple Bloch lines. Transfer is performed using a bias pulse magnetic field as in the conventional example. In the information read operation, the end of the transfer path is extended, and the Bloch line pair is moved to the end of the extended domain by the in-plane magnetic field. Thereafter, the domain ends are cut with a hairpin conductor. The cleaved domains are shown in Figure 3 (a), (b), and (c).
It has a winding number (S number) corresponding to the number of Bloch lines, as shown in FIG. Therefore, the cut domain is driven by a bias magnetic field gradient caused by a current pulse from the parallel current applying conductor 7 as shown in FIG. can be detected,
Information can be read.

As described above, the magnetic memory element of the present invention can achieve high storage density without causing the problem of phosphorography in element fabrication, which has been a problem in the past when improving storage density. This will greatly contribute to the practical application of the device.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of the main parts of a magnetic memory element according to the present invention, FIG. 2 is a diagram showing the configuration of a conventional magnetic memory element, and FIGS. 3(a), (b), (c) is a diagram showing the domain wall state of a cut domain during a read operation and a domain cutting operation, respectively, and FIG. 4 is a diagram showing a method of detecting the winding number of a cut domain. 1 Transfer path by varnish drive domain, 2: State of two Bloch line pairs, 3: State of Bloch line pair O,
4: A state in which there is one pair of Bloch lines, 5: A row of patterns forming a transfer unit by ion implantation at intervals of 14 am,
6: In-plane magnetic field, 7: Conductor for applying parallel pulse current.

Claims (2)

[Claims] (1) A stripe existing in a soft magnetic ferromagnetic material (including ferrimagnetic material) film that has information reading means, information writing means, and information storage means and whose easy magnetization direction is perpendicular to the film surface. In a magnetic memory element having a means for driving vertical Bloch line pairs, each consisting of two adjacent vertical Bloch lines formed in the Bloch domain wall at the boundary of a domain, within the Bloch domain wall, the element 1. A method of driving a magnetic memory element, the method comprising driving a magnetic memory element. (2) The method for driving a magnetic memory element according to claim 1, characterized in that the domain wall state of the cut domain is detected as an information reading method.