JPH01220197A - Method for fixing stripe magnetic domain - Google Patents

Abstract

PURPOSE:To easily and stably fix a stripe magnetic domain by setting a bias magnetic field to a prescribed range with a local magnetic field due to a local magnetic field generating means, which is necessarily arranged, in a Bloch line memory. CONSTITUTION:A bias magnetic field 10 is added and the magnetization of a stripe magnetic domain holding layer is saturated in a same direction as the magnetization in the magnetic domain which is stabilized around a groove 4. After that, when a pulselike current is given to a magnetic domain generator 8 in an arrow direction and the bias magnetic field is set to the prescribed range, the magnetic domain to enter a pattern notch 13 goes over the groove 4 and satisfactorily achieves the area of an auxiliary groove 7. Next, when the pulselike current is impressed to a magnetic domain generator 9 in the same direction as the arrow, the magnetic domain 11 are mutually connected in the both edge parts of the groove 4 and a magnetic domain 12 is formed to be enclosed by a close magnetic wall which surrounds the groove 4. Further, an external magnetic field is made '0' and the current is increased in the reverse direction the magnetic domain for Bloch line holding, which has the magnetic wall to surround the groove 4 can be easily and stably fixed without changing the bias magnetic field.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a Ploch line memory, and relates to a method for fixing striped magnetic domains serving as a Ploch line transfer path.

(Prior art) Regarding the conventional fixing method of striped magnetic domains, Patent No. 61
-290887. This is shown in FIGS. 5 to 7.

First, the magnetization of the striped magnetic domain holding layer 1 is changed using a bias magnetic field 1.
By adding 0, the magnetization is saturated in the same direction as the magnetization in the magnetic domain stabilized around the groove 4.

Applying a current in the direction of the arrow to the magnetic domain generator 8 causes the magnetic field to generate a magnetic domain 11 along the upper edge 12 of the magnetic domain generator 8 (Fig. 5), and then increases the current to generate a magnetic domain inside the notch 13 as well. (Figure 6). By reducing the absolute value of the bias magnetic field 10, the magnetic domain 11 is extended past the area sandwiched between the trenches 4 to the area 21 on the opposite side from the magnetic domain generator 8. After that, a current is applied to the magnetic domain generator 9, and the magnetic field causes the magnetic domain 11 to extend to the region 21.
is cut to form a magnetic domain surrounded by a closed domain wall surrounding the grooved portion 4.

However, experiments have shown that with this method, there is a considerable difference in the magnitude of the bias magnetic field that changes the bubble domain into a stripe domain between regions where the grooves are lined up in parallel and regions where there are no grooves. It was found that there is a drawback in that the magnetic domains do not elongate in the trench region unless the bias magnetic field is lower than in other regions. When the bias magnetic field is lowered until the magnetic domain extends in the region between the grooves in the region including the grooved portions, it will extend in any one place in the grooved portions, and the magnetic domain will extend on the side opposite to the side where the magnetic domain generator 8 is located. As soon as the conductor button 9 for magnetic domain coupling comes out to the area 21, the magnetic domain expands and a stray diagram-shaped magnetic domain is formed in the area 21 (FIG. 7). For this reason, the magnetic domain that has been extending through the grooved region behind the currently extended magnetic domain is obstructed by the stray diagram-shaped magnetic domain and cannot extend to the point where it crosses under the conductor batten 9 for joining the magnetic domains. therefore,
It has been difficult to extend the magnetic domain once formed by a magnetic domain generator from one tip region of the grooved region to the other tip region with good control by lowering the bias magnetic field. In addition, the conventional method requires changing the bias magnetic field, and has the drawback that striped magnetic domains, which serve as Ploch line transfer paths in Ploch line memory, cannot be easily formed.

(Problems to be Solved by the Invention) The above-mentioned method has been problematic in order to stably arrange a large number of magnetic domains. An object of the present invention is to provide a method for fixing striped magnetic domains that eliminates these drawbacks and simplifies the conditions for applying an external magnetic field for stably arranging striped magnetic domains.

(Means for Solving the Problems) The above object is a ferromagnetic material (including a ferrimagnetic material) having an information reading means, an information writing means, and an information storage means, and whose easy magnetization direction is perpendicular to the film surface. In a method of fixing a striped magnetic domain having a domain wall surrounding a strip-shaped groove provided in at least a part of the film, a local magnetic field is generated using a local magnetic field generating means provided in one tip region of the political situation, and a bias magnetic field is generated. This is achieved by fixing stripe magnetic domains by setting them in advance in a predetermined range and generating magnetic domains extending from one tip region to another tip region.

(Example) An example of the operation of stripe magnetic domain stabilization will be explained using FIGS. 1 to 3. First, the magnetization of the striped domain holding layer is saturated in the same direction as the magnetization in the magnetic domain stabilized around the groove 4 by applying a bias magnetic field 10.

Thereafter, a current is applied to the magnetic domain generator 8 in the direction of the arrow, and the resulting magnetic field generates magnetic domains shown at 11 in FIG. At this time, it is important to set the bias magnetic field 10 to a predetermined range in advance, so that the bias magnetic field prevents the magnetic domain that has entered the button notch 13 from passing through the trench and reaching the area where the auxiliary groove 7 is located. This can be achieved by keeping it constant. This bias magnetic field may be within a range in which the striped magnetic domains can exist in a natural state (a state in which no local magnetic field is applied). Further, it is desirable to apply a pulsed current to the magnetic domain generator 8. This generates a magnetic domain 11 (the magnetization within the magnetic domain 11 is in the opposite direction to the bias magnetic field 10), which is formed by locally reversing the once saturated magnetization (the same direction as the bias magnetic field 10) of the striped domain holding layer. It's for a reason. The shape of the generator 8 is as follows:
The shape was designed to generate magnetic domains that entered the batten notches 13 along the lines 2 (FIG. 4). The magnetic domain extends past the grooved portion to the area where the auxiliary groove 7 is located, as shown in FIG. Thereafter, a pulse current is applied to the magnetic domain generator 9 in the direction of the arrow shown in FIG. 2 to form magnetic domains as shown in FIG. Due to these magnetic fields, the magnetic domains 11 are joined to each other at both ends of the grooved portion, and conversely, a magnetic domain 12 surrounded by a closed domain wall surrounding the grooved portion is formed. When the externally applied magnetic field is reduced to zero, and then its direction is reversed to the direction indicated by 10 and the strength of the magnetic field is increased, a magnetic domain having domain walls surrounding the groove is formed as shown in FIG. 3. 14 is a hollow magnetic domain, and 15 is an outer domain wall of the magnetic domain.

This magnetic domain is used for holding Ploch line pairs in the Ploch line memory. In this way, the magnetic domain surrounded by the domain wall surrounding the groove 4 could be stabilized.

A 4 pm bubble material (YSmLuCa) 3 (FeGe) 50.2 garnet film was grown by LPE to a thickness of 2 pm on a GdaGas012 (111) substrate. FIG. 1 is an example of the main part of a striped magnetic domain retaining layer when the method of the present invention is used.

Here, 4.6.7 is a hollowed out portion of the magnetic domain holding layer, and 10 is a bias magnetic field. A groove 4 is formed in a region on the striped magnetic domain holding layer 1 where the magnetic domain is to be held, and auxiliary grooves 7 are formed along the groove to sandwich separated regions.

Grooves 4, 6, and 7 were formed by selectively implanting ions into the portion where the trench was to be dug, and then etching using phosphoric acid. The depth of the groove created was 2.111 m. Groove 4 has a width of 31
1 m, and the arrangement periodicity is 2 μm. A magnetic domain generator having the shape shown in FIG. 4 was placed thereon with a 0.5 pm SiO□ spacer interposed therebetween. A pulse current generator and a direct current source are connected to the magnetic domain generator and local in-plane magnetic field generating means 8.9 arranged at both ends of the groove 4, respectively, so that a desired local magnetic field can be applied. In addition, in 8.9, magnetic domains can be generated with good controllability so that the comb-shaped comb eye shown at 11 is located at the entrance of the area between each groove of the groove, and the magnetic domains are generated adjacent to each other extending from the groove 4. A magnetic domain generator having the shape shown in FIG. 4 was used so that matching magnetic domains 11 could be sewn together. In FIG. 4, 12 is a pattern edge, and 13 is a pattern notch.

Here, an auxiliary groove 7 is provided in the notch part of the conductor pattern for sewing shown in FIG. 9, and a structure is shown in which the tip of the magnetic domain 11 shown in FIG. 1 is extended straight with good controllability. However, using this method, a magnetic domain having the shape shown in FIG. 1 can be obtained. Using the magnetic domain in the state shown in FIG. 1 as a starting point, the magnetic domain 14 having a closed domain wall surrounding the grooved portion 4 shown in FIG. 3 was formed with good controllability by a series of operations starting from the generation of the magnetic domain described above.

(Effects of the Invention) According to the present invention, a magnetic domain extending from one end of the trenching portion to the other end can be formed by the local magnetic field created by the current applied to the magnetic domain generator without changing the bias magnetic field. It has become possible to form striped magnetic domains surrounding the area with good controllability, and it has become possible to easily form a transfer path for Ploch line pairs in a Ploch line memory.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the main structure for maintaining magnetic domains using the present invention. FIG. 2.3 is a diagram showing the magnetic domain formation process of the present invention. FIG. 4 is a diagram showing an example of a magnetic domain generator used in the present invention. 5 to 7 are diagrams showing an example of a conventional magnetic domain stabilization method using a closed domain wall surrounding a grooved portion. In the figure, 1... magnetic domain holding layer, 4... magnetic domain holding layer hollowed out part, 6... magnetic domain holding layer hollowed out part for guard,
7... Auxiliary magnetic domain holding layer hollowed out part, 8.9...
Conductor pattern for magnetic domain generation, 10... Bias magnetic field, 11
...Magnetic domain generated by the magnetic domain generator 8, 12...Edge of conductor pattern for magnetic domain generator, 13... Notch of conductor pattern for magnetic domain generation, 14... Hollowed out magnetic domain, 15...
・Magnetic domain outer domain wall.

Claims (2)

[Claims] (1) A strip-shaped film provided on at least a portion of a ferromagnetic material (including ferrimagnetic material) film having an information reading means, an information writing means, and an information storage means, and whose easy magnetization direction is perpendicular to the film surface. In a method for fixing a striped magnetic domain having a domain wall surrounding a groove, a local magnetic field is generated by a local magnetic field generating means provided at one tip region of the groove, and a bias magnetic field is generated within a predetermined range. A method for fixing a striped magnetic domain, comprising fixing a striped magnetic domain having a domain wall surrounding a groove using a striped magnetic domain extending from one tip region to another tip region. (2) The method for fixing striped magnetic domains according to item 1, wherein the local magnetic field is a pulsed magnetic field.