JPH071633B2 - Magnetic memory element - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a nonvolatile ultra-high density solid-state magnetic memory element.

(Prior Art) A magnetic bubble element has been conventionally developed as a target for a high-density solid magnetic memory element. However, with the garnet materials currently used, the smallest bubble diameter that can be reached is
It is said to be 0.3 μm. Therefore, a bubble material that holds bubbles having a diameter of 0.3 μm or less must be determined in addition to the garnet material. This is not easy and is even thought to be the limit of bubble densification.

As a super-high density solid magnetic memory element capable of significantly improving the densification limit based on such characteristics of the valve holding layer and keeping the information read time at the same level as the conventional element, A Bloch line pair consisting of two vertical Bloch lines that are statically and stably present in the Bloch domain wall that forms the boundary of the stripe domain formed in the ferromagnetic (including ferrimagnetic) film with the easy magnetization direction. Hereinafter, an element using a VBL pair) as a memory unit was invented (Japanese Patent Application No. 57-182346).

One of the most important parts of this device is VBL
Stabilized in the stripe domain domain wall in the form of a pair, and
The VBL pair is transferred within the Bloch domain wall as needed.

Regarding the VBL vs. stable holding method, in Japanese Patent Application No. 58-065826, by locally changing the direction of magnetic anisotropy in the film plane along the Bloch domain wall around the stripe domain forming the minor loop, It has been shown that along the stripe domain domain walls, VBL pairs can be engineered into stable and non-stable positions.

(Problems to be Solved by the Invention) A specific method for locally changing the direction of the magnetic anisotropy in the film plane described in Japanese Patent Application No. 58-065826 is (1) Selective to the film Utilizing the inverse magnetostriction effect based on the lattice strain due to ion implantation, or (2) forming a pattern on the surface of the stripe domain holding film using a material with a large internal stress to give a stress distribution to the film, and the inverse magnetostriction effect based on it Utilizing IEEE Transaction on Magnetics V
ol, MAG-20, No.5pp1135 to 1137 (1984).
In (1), the direction of the in-plane magnetic anisotropy of the film is controlled only in the film surface layer portion. This local change of in-plane magnetic anisotropy is a method of controlling only the difficulty of the VBL pair without changing the moving velocity of the domain wall. Therefore, there is no problem if the in-plane magnetic anisotropy is uniformly controlled in the film thickness direction, but only a part of the in-plane magnetic anisotropy is changed, and the surface layer is not ion-implanted. If the boundary with the layer is clear, the gyro force generated for a given domain wall motion velocity is constant, so depending on the difficulty of movement of the VBL pair, the movement of the VBL pair is inevitably It becomes non-uniform along the film thickness direction. As a result, in some cases, VBL may be divided in the middle part of the film thickness, and VBL pairs may disappear. This becomes a big problem from the reliability of the device,
In order to remove this obstacle, it is desirable to uniformly implant ions in the film thickness direction, but it is quite difficult because of the essential characteristics of the ion implantation method or the performance of the ion implantation device.
The method (2) has a slower change in the in-plane magnetic anisotropy in the film thickness direction than the method (1), and VB is smaller than that of the method (1).
The probability of destabilization during L pair movement is small, but the tendency is the same as in ion implantation.

The purpose of the present invention is to eliminate the above-mentioned conventional problems in VBL.
An object of the present invention is to provide an ultrahigh density recording element having a stripe domain domain wall subjected to the anti-stable method.

(Means for Solving the Problem) That is, the present invention is present in a ferrimagnetic film having an information reading unit, an information writing unit and an information storage unit, and having a direction perpendicular to the film surface as an easy magnetization direction. A vertical Bloch line pair composed of two adjacent vertical Bloch lines formed in the Bloch domain wall at the boundary of the stripe domain is used as a memory information unit, and means for transferring the vertical Bloch line pair in the Bloch domain wall In the device, another type of ferrimagnetic material is directly attached to the surface of the stripe domain holding layer to locally change the two film thicknesses along the stripe domain domain wall.

(Operation) The present invention has shown that, by adopting the above-mentioned configuration, the VBL pair, which is an information unit, can be stably held and transferred along the stripe domain domain wall. Hereinafter, the principle of the present invention will be described in detail. One of the reasons why sufficiently stable transfer of VBL pairs cannot be obtained is that VBL pairs disappear during transfer. The mechanism by which VBL disappears is due to the structure of VBL changing along the thickness direction of the stripe domain retention layer. The structure of VBL changes along the film thickness direction of the stripe domain holding layer because the stripe domain holding layer is a thin film and has a direction of easy magnetization in the direction normal to the holding layer film surface. This is because the magnetic pole is induced and there is an in-plane magnetic field Hs induced from the magnetic pole to the domain wall portion in the domain wall normal direction.

Figure 4 shows the situation. Both sides of the stripe domain 3 are surrounded by Bloch domain walls 4, 4 '. πΔ ₀ is the width of the domain wall. The outside of the domain wall 4 has a magnetization 5'in the opposite direction (upward) to the direction (downward) 5 of the magnetization M in the stripe domain. Therefore, on the film surface of the stripe domain portion 3 of the stripe domain holding layer, a − magnetic pole is induced on the upper side and a + magnetic pole is induced on the lower side. On the other hand, in the regions outside 4,4 ', a positive magnetic pole is induced on the upper film surface and a negative magnetic pole is induced on the lower side. As a result, an in-plane magnetic field Hs is generated in the direction normal to the magnetic wall surface near the film surface of the magnetic walls 4, 4'having planes parallel to the direction normal to the film surface. In the case of FIG. 4, the orientation of Hs is 4 on the upper surface of the membrane to the right and on the lower side to the left, and for 4 ', on the upper surface of the membrane to the left and on the lower side to the right. Due to the influence of Hs, the direction of magnetization on the center line of the domain wall is gradually rotated from the lower side to the upper side of the film surface in the direction 4 from the left side to the right side on the upper surface of the film. Within 4 ', the lower side faces right, and the upper side faces left. The change in the film thickness direction of the domain wall structure also has a great influence on the VBL characteristics. FIG. 5 shows the state of rotation of the magnetization of the VBL portion 11 in the bubble domain domain wall with respect to both surfaces of the stripe domain holding layer and the central portion of the film thickness. The magnetization of the center of this VBL is directed to the central axis of the bubble domain along the surface normal of the bubble domain domain wall. In this case, the in-plane magnetic field Hs is oriented toward the central axis of the bubble domain on the upper surface of the bubble domain and outward on the lower side. The magnetization on the centerline of the domain wall is aligned in the Hs direction near the film surface. However, near the center of the film thickness, the contributions from the upper and lower surfaces cancel each other out to zero, and the magnetization at the center of the domain wall becomes the original magnetization direction of the Bloch domain wall (parallel to the domain wall surface). When the VBL is present in the domain wall having such a property, the magnetization on the center line of the VBL is oriented in the same direction as the surrounding magnetization on the upper surface of the film, and no particular energy can be stored in the VBL region. On the other hand, on the lower surface, the direction of magnetization of VBL differs from the direction of domain wall magnetization around it by 180 °, so exchange energy is stored in VBL. Therefore, the energy E _L of VBL changes along with the film thickness.

FIG. 6 qualitatively shows this state. It is the result of calculating the energy E _L per unit length of VBL with respect to the film thickness h of the stripe domain holding layer.

When the left end of the horizontal axis in FIG. 6 is the lower surface of the film and the right end is the upper surface of the film, the dependence of E _L of VBL in FIG. 5 on the film thickness direction is represented by 12. E _L is very high at the bottom of the membrane. On the other hand, VBL
When the magnetization on the center line is directed outward in the direction of the bubble domain domain wall normal in FIG. 5, the film thickness direction dependence of E _L as shown in FIG. 6'is obtained.

Through such E _L film thickness direction dependence of the following processes, leading to disappearance of VBL pairs. FIG. 7 shows VBL in the Bloch domain wall in the stripe domain holding layer. 11,1
1'is a VBL structure used as an information carrier in the present invention. 11
12 and 11 'in FIG. 6 correspond to 12'. 11 or 1
The magnetization on the center line of 1 ′ VBL is aligned in the same direction along the domain wall normal direction over the film thickness direction. On the other hand, 13 VB
The magnetization on the center line of L is opposite in direction between the lower side and the upper side at the boundary of the film thickness center. The magnetization agrees with the direction of Hs in both parts. At this time, there is a singular point 14 called Bloch point in the center of the film thickness. By including this point, the change of E _L becomes small in the film thickness direction. That E _L of the VBL is 'varies along, the upper half changes along 12 11, 11' 12 in the lower part of the film center in FIG. 7 as, E _L is the film thickness direction Rapid changes along the way were avoided. However, when the Bloch point is inserted, the polarity of VBL is reversed in the upper half and the lower half.

In this Bloch line memory, the gyro force, which is the reaction that occurs when a pulse bias magnetic field is applied to the domain wall, is used to move the information carrier VBL along the stripe domain domain wall. This gyro power is VBL
The direction of movement is determined depending on the polarity of. Therefore, the seventh
As shown in Figure 13, VBLs that share the opposite polarity eventually
It cannot move in the pulse bias magnetic field. When adjacent VBLs that cannot move to each other collide with each other, portions of the two VBLs having different polarities are recombined and the Bloch lines eventually disappear as a whole. This is a very big problem for general-purpose devices.

Bloch point injection into VBL occurs when kinetic energy equal to the Bloch point generated magnetic field energy is applied to VBL by domain wall motion. In order to suppress the Bloch point implantation, the Bloch point implantation energy may be increased. That is, the structure may be such that the Bloch points are hard to enter.

Based on such an idea, the object of the present invention is to eliminate the conventional drawbacks, to stably hold the VBL pair on the stripe domain domain wall which is a minor loop, and to enable selective transfer bit by bit. An object of the present invention is to provide an ultra-high density magnetic memory element that uses as a data unit.

According to the present invention, a magnetic storage element using as a storage unit a VBL pair composed of two adjacent VBLs formed in a Bloch domain wall around a stripe domain existing in a ferrimagnetic film having an easy magnetization direction perpendicular to the film surface In, by directly attaching to at least one surface of the ferrimagnetic material a ferrimagnetic material film in which the manner of contribution is reversed compared to the manner of contribution from the case-constituting atoms to the direction of spontaneous magnetization of the ferrimagnetic material. , The Bloch point generated magnetic field energy is controlled. In ferrimagnetic materials, it is possible to form magnetic materials in which the contributions from each constituent atom to the spontaneous magnetization are reversed, see, for example, Satoshi Chikazumi, "Physics of Ferromagnetic Materials".
As described on pages 78 to 79 of (Shokabo, September, 1959), garnet, which is an example of a ferrimagnetic material, has Fe ³⁺ located at the 16a position of the cubic structure. Since the magnetization direction of Fe ³⁺ located at the 24d position is opposite, it is clear that the direction of spontaneous magnetization can be reversed by controlling the amount of Fe ³⁺ located at each lattice position. . The position of 16a or 24d in the cubic structure is described on page 80 of “Magnetic Bubble” (Maruzen, October 1972) edited by Shuichi Iida et al. Regarding garnet crystals. A detailed description of the configuration will be given below.

FIG. 1 is a diagram showing a general configuration of the present invention. In the figure, 2 is a ferrimagnetic coating layer whose film thickness is locally changed. FIG. 8 is a constitutional view of the stripe domain holding layer of the minor loop portion in the present invention, and in FIG. 8, the local change of the film thickness of the ferrimagnetic coat layer in the present invention is not shown. A ferrimagnetic material layer 1 for holding a strap domain is attached on a substrate 7. On top of that, the ferrimagnetic layer 2 in which the manner of contribution is reversed as compared with the manner of contribution from the case-constituting atoms to the direction of the spontaneous magnetization of the ferrimagnet is directly attached. By doing so, the energy density E _{L of} VBL can be suppressed from rapidly increasing on the film surface. The mechanism will be described by taking a general ferrimagnetic garnet film as an example of the material for the stripe domain holding layer. 9th
In the figure, 11 and 11 'are VBLs. VBL11,11 'from the film thickness direction dependence of the energy density (Figure 7), E _L is higher at the lower end of 11 the film, 11' E _L becomes high in the vicinity of the top surface of the membrane. On the upper surface of the stripe domain holding layer 1 shown in FIG. 8, a ferrimagnetic material 2 in which the manner of contribution is reversed as compared with the manner of contribution of each constituent atom to the direction of spontaneous magnetization of 1.
In this way, the exchange energy is stored in the upper end 15 of the VBL 11 at the boundary between 1 and 2. Because the magnetic domain structure of the ferrimagnetic layer 2 depends on the domain structure of the stripe domain holding layer 1, the magnetization direction of 2 near the domain wall existing in 1 is the direction of the in-plane magnetic field component Hs generated from the domain structure of 1. Directed to. Now, assume that the magnetization of layer 1 is oriented in the same direction as the atomic magnetic moment at the 24d position, and the magnetization of layer 2 is aligned with the orientation of the atomic magnetic moment at the 16a position. 24d
When the atomic number is 64 or more, the contribution of the atomic magnetic moment of the rare earth io at the position is the same as the direction of the atomic magnetic moment at the 16a position. Consider the relative magnitude of the atomic magnetic moment at the position and the atomic magnetic moment at the 24d position. The direction of magnetization per unit lattice is the sum of atomic moments at the 16a position and 24d.
Compare with the sum of atomic magnetic moments at the positions and agree with the larger one.

In other words, the fact that the magnetization is oriented in the Hs direction near the upper end of VBL means that the atomic magnetic moment at the 24d position matches the Hs direction, and the fact that the magnetization is oriented in the Hs direction in layer 2 is The atomic magnetic moment at the 16a position agrees with the Hs direction. Thinking this way, VBL1
At the boundary 15 between the upper end of 1 and 2, the atomic magnetic moment at the 24d position of layer 1 and the atomic magnetic moment at the 16a position of layer 2 have the same direction. This is contrary to the property that the atomic magnetic moment at the 24d position and the atomic magnetic moment at the 16a position are coupled antiparallel to each other and are stabilized in the ferrimagnetic garnet. Therefore, the exchange energy is stored in the 15th part.

This exchange energy changes the magnetization direction of the ferrimagnetic layer of 2 to Hs
In either case, the magnetization is reversed in the opposite direction, or the magnetization near the upper end of VBL11 is reversed.
The Bloch point injected at the position of cannot be easily advanced to the film thickness center of 1. In order for the Bloch point to reach the center of the film thickness of 1, the film thickness of 2 is increased so that the magnetization of 1 is reversed, and in the film thickness direction dependence of E _L shown in FIG. It is necessary that E _{L at the} upper end of the film thickness of the curve shown in is larger than the value at the center of film thickness. The point where E _{L at the} upper end of the film thickness becomes equal to E _L at the film thickness center determines the limit thickness of the film 2 to be placed on 1 so as not to advance the Bloch point to the film thickness center of 1. On the other hand, at the boundary between the upper end of VBL11 ′ and 2, the atom at the 24d position and the magnetization and 16a of the genus 2
The magnetization is coupled in the opposite direction to the position magnetization, and the arrangement is such that the property of stable coupling peculiar to the ferrimagnetic material garnet is satisfied. Therefore, no exchange energy can be stored in 16 parts. Rather, VBL1 reflecting the magnetic domain structure of 1
Hs at the upper end of 1'orients the magnetization at the 16a position of layer 2 in the same direction as Hs, so the magnetization direction near the upper end of VBL of 1 is H
It will be stabilized in the opposite direction to s. For this reason, when the film of 2 is not present, it is relatively easily reversed in the Hs direction, and the Bloch point injection at the 16 points where Bloch points were injected can be suppressed.

FIG. 10 is another example of the present invention, and in FIG. 10 as well, the illustration of the local change in film thickness of the ferrimagnetic coating layer in the present invention is omitted. In this example, between the lower surface of the stripe domain holding layer 1 and the substrate, as in the upper surface, the manner of contribution is reversed as compared with the manner of contribution from each constituent atom to the direction of spontaneous magnetization of 1. The body membrane 2'is attached so as to be in direct contact. By doing so, Bloch point injection from both upper and lower surface layers of the stripe domain holding layer is suppressed.

FIG. 11 illustrates the mechanism. At the bottom of VBL11 is VBL
The same structure as the upper end of 11 'is realized, and VBL at the lower end of 11' is VBL
The same structure as at the top of 11 appears. From this, the Bloch line 11 from which the Bloch point easily enters from the lower end of the striped May retaining layer 1 is suppressed from being injected from the Bloch point 16 'by the layer 2'. On the other hand, the Bloch line 11 ′ from which the Bloch point easily enters from the upper end of the try domain holding layer 1 is prevented from being injected from the Bloch point 16 by the layer 2. in this way,
On the surface of the stripe domain holding layer (ferrimagnetic material), at least one surface of the ferrimagnetic material is reversed in the manner of contribution as compared with the manner in which the constituent atoms contribute to the direction of the spontaneous magnetization of the ferrimagnetic material. It was found that the direct coating of the ferrimagnetic film is perturbed by the VBL energy. This principle is used for stable position setting of VBL pairs.
FIG. 1 shows how to change the film thickness in the stripe domain domain wall portion according to the present invention. VBL in the domain walls (Bloch domain walls) on both sides of stripe domain 3 vs. V in 6
BL11 'is stabilized in the thick part and VBL11 is stabilized in the thin part. Since the magnetization direction of 11 'is opposite to the magnetization direction of the coat layer, only the exchange energy between the atomic magnetic moments of both layers is obtained. On the other hand, in 11, the magnetization direction is the same as the magnetization direction of the coat layer, so that the presence of the coat layer increases the VBL energy by the amount of exchange energy, and thus stabilizes in a thin coat layer. . Note that keeping these two VBLs as a pair is due to the contribution of the in-plane magnetic field applied from the outside in the domain longitudinal direction in addition to the interaction between the VBLs.

In the conventional VBL vs. stability method, the energy density of VBL is locally changed along the domain wall. In order to make this change, specifically, ion implantation or the like is used, and therefore it is unavoidable that the characteristics become nonuniform in the film thickness direction.
The VBL pair 6 moves in the Bloch domain wall by the gyro force generated by the pulse bias magnetic field applied in the direction perpendicular to the film surface of the ferrimagnetic film forming the stripe domain. Therefore, the moving speed of the VBL becomes non-uniform along the film thickness direction, and the VBL is divided.

On the other hand, in the VBL pair stabilizing method of the present invention, nothing is processed on the layer holding the VBL pair. The existence of the coat layer merely causes the VBL to interact with the coat layer, thereby eliminating the drawbacks of the conventional method.

The principle will be described with reference to FIG. FIG. 2 (a) shows a cross section obtained by cutting a part of FIG. 1 with a plane including the stripe domain domain walls. Two Vs that form a VBL pair 6
BL11 and 11 'are respectively stabilized in the thick and thin areas of the coating layer. In order to transfer this VBL pair, a pulse bias magnetic field is applied in the direction perpendicular to the film surface, and the gyro force generated thereby is used. We will describe how to evaluate the magnitude of gyro force.
In Fig. 2 (b), the stable positions of VBL11 and 11 'are shown as coating layer and VB.
From the viewpoint of interaction with L, it is qualitatively shown in correspondence with FIG. Generally, the VBL, which is stabilized at the point where the interaction between the VBL and the coat layer is the lowest, moves over to the valley next to it, overcoming the peak where the interaction between the VBL and the coat layer is the maximum. Therefore, the gyro force acting on the VBL pair must be larger than the maximum value of the gradient of the change in the interaction between the valley and the peak of the interaction. The advantage of the present invention is that VBL is driven by V
The bottom of the potential at which BL11 'is stabilized rises, and the so-called bit barrier between adjacent stable positions becomes relatively low. This is the so-called hrgh coat layer
-Because it belongs to the -g material, there is a large difference in the gyroscopic force that acts on the VBL portion between the stripe domain holding layer and the coat layer for the dynamic movement of a given domain wall, and the exchange force increases dynamically. Will avoid that position. Then, when the dynamic movement of the domain wall subsides, the thick position of the coat layer again makes the potential well deepest for VBL 11 ′, and VBL 11 ′ is stabilized there.

Next, how to change the film thickness of the coat layer will be described. Second
The broken line in FIG. 10A shows the case where the film thickness change region is extremely narrow (rectangular cross section). Correspondingly, the x-direction dependence of the interaction between VBL and the coating layer also changes as shown by the broken line in FIG. 2 (b). In this case, the gyroscopic force required to move the stabilized VBL to the valley next to it where the energy is low is much larger than that in the case of the solid line, and is actually difficult to control. Therefore, the corrugated structure shown by the solid line is practically easy to use.

In this method, since the stripe domain holding layer is not processed at all, the response of the VBL pair to the gyroscopic force does not change discontinuously in the film thickness direction as in the ion implantation method. Therefore, the probability of causing instability such as VBL being divided at the middle portion of the film thickness when overcoming the inter-bit barrier during transfer is suppressed to a very low level, and stable VBL pair transfer can be obtained.

The contents of the invention will be specifically described below with reference to examples.

Example 1 A method of manufacturing this wave pattern will be described with reference to FIG.

A pattern 8 having a width of 5 μm, a period of 10 μm and a film thickness of 1 μm is formed on the bubble material film 2 with a positive photoresist MP1300 (trade name, Shipley Japan Co., Ltd.) (FIG. 3A). After pattern formation, post bake is performed at 135 ° C. for 1 hour. Then, the pattern becomes a shape like 8 '. If viking is performed at a temperature higher than this temperature, the pattern width fluctuates, which is not preferable.
Conversely, if the temperature is too low, the cross-sectional shape of the pattern remains rectangular, which is not preferable (Fig. 3b). Then the molecular weight
17500 polystyrene is applied with xylene as solvent. Using a solution in which 10 weight percent of styrene is dissolved,
At a spin coating rotation speed of 3000 rpm, a polystyrene coating film 9 having a role of 3000 Å is obtained in the flat portion. The surface after application had a gentle waveform. The height difference of the corrugated shape was about 1.3 μm. There was no deformation of the positive photoresist pattern before and after the coating process (Fig. 3c). Next, ion implantation is performed. The implantation conditions were set so that the ions would penetrate through a 1.3 μm thick organic film.

Here, 130 KeV / He / 4.8 × 10 ¹⁵ pieces / cm ² , 50 KeV / He / 1.7 × 10
^{It was set to 15} pieces / cm ² . Ions are implanted into the portion of the layer coated on the surface of the stripe domain holding layer shown in FIG. 3 (d) 10 '. It is known that when ion-implantation is performed on the coating layer material, lattice strain is induced in the implantation layer, and thus the chemical etching resistance is generally changed. After removing 90
When it was immersed in phosphoric acid at 0 ° C. for 10 minutes, the coating layer could be processed into a corrugated shape with a height difference of 0.4 μm as shown in FIG. 3 (e).

The stripe domain holding material is Gd ₃ Ga ₅ O ₁₂ (111)
5μm bubble material (YSmLuCa) ₃ (Fe
Ge) ₅ O ₁₂ film (thickness = 3.88 μm, stripe width = 5.0 μ
m (4uMs = 202Gauss directly on (EuCa) ₃ (siGeFe)
Liquid phase epitaxial growth of ₅ O ₁₂ was performed. Stability of VBL pair was determined by arranging the strap domain in this region for the sample with 5μm period (mask pattern width of 3μm or 2μm) and peak height of 0.4μm as shown in Fig. 1. It was confirmed that the VBL pairs were stabilized at the peaks and valleys of the wave-like structure.When a rectangular wave pulse bias magnetic field with a width of 10 ns was applied to the VBL pairs, the VBL
The pair overcame a mountain with a corrugated structure.

When the ferrimagnetic coat layer 2'is formed below the stripe domain holding layer 1 as shown in FIG. 10, after the ferrimagnetic coat layer 2'is epitaxially grown on the substrate 7, it is shown in FIG. After forming a local corrugated film thickness change in the same manner as in Example 1, the stripe domain holding layer 1 is formed by epitaxial growth. Since both the ferrimagnetic coat layer and the stripe domain holding layer are single crystal films grown by epitaxial growth, there is no problem in film growth even if there is a local change in film thickness.

(Effects of the Invention) According to the present invention, stabilization of Bloch line pairs on a stripe domain domain wall, which is one of the most important elements in a Bloch line memory, and stability of transfer along the domain wall, compared to conventional methods. I was able to improve.

[Brief description of drawings]

FIG. 1 is a schematic view of a stabilizing holding means for a vertical Bloch line according to the present invention, and FIGS. 2 (a) and 2 (b) are respectively ferrimagnetic stripe domain holding layers and ferrimagnets when cut along a plane including a domain wall. It is a figure which shows the cross section of a body coat layer, and the position dependence of the interaction of a Bloch line and a coat layer. FIG. 3 is a diagram showing an example of a process of forming an element.
FIG. 4 is an explanatory diagram of the film thickness direction dependence of the magnetization direction on the domain wall centerlines on both sides of the stripe domain, FIG. 5 is a diagram showing the state of magnetization rotation of the VBL portion in the bubble domain domain wall, and FIG. 6 is the VBL.
FIG. 7 is a diagram showing the dependence of the energy density E _L per unit length in the film thickness direction, FIG. 7 is an explanatory diagram of various VBL existing in the stripe domain domain wall, and FIGS. 8 and 9 are configuration examples of the stripe domain holding layer. Figure and its basic principle explanatory diagram,
Figures 10 and 11 show another example of the structure of the stripe domain retention layer and its basic principle. In the figure, 1 ... ferrimagnetic material stripe domain holding layer, 2,2 '... ferrimagnetic material coating layer, 3 ... stripe domain, 4,4' ... stripe domain domain wall, 5
...... Magnetization in stripe domain, 5 '…… Magnetization outside stripe domain, 6 …… Vertical Bloch line (VB
L) Pair, 7 ... Substrate, 8 '... Post-bake photoresist pattern, 9 ... Polystyrene, 10' ... Ion-implanted ferrimagnetic coating layer, 11, 11 '... Vertical Bloch line (VBL) ), 12 …… Dependence curve of energy density of VBL11 in the stripe domain retention layer thickness direction, 1
2 '... VBL 11' energy density-dependent curve in the stripe domain retention layer, VBL with 13 ... Bloch points, 14 ... Bloch points.

Claims (1)

[Claims] 1. A vertical block formed in a Bloch domain wall around a stripe domain existing in a ferrimagnetic film having an information reading unit, an information writing unit, and an information storage unit and having a direction perpendicular to a film surface as an easy magnetization direction. In a magnetic memory element using a line pair as a memory information unit, the manner of contribution is reversed on at least one surface of the ferrimagnetic material film as compared with the manner of contribution from each constituent atom to the direction of spontaneous magnetization of the ferrimagnetic material. The magnetic storage element is characterized in that the ferrimagnetic film is directly coated, and the film thickness of the coating layer is locally changed along the Bloch domain wall of the stripe domain holding layer.