JPS6337803A - Information transfer method of bloch line memory - Google Patents

Abstract

PURPOSE:To permit stable, high-speed and good information transfer of a Bloch line memory with simple constitution by forming periodic potentials having directivity along magnetic wall parts and impressing impulsive magnetic fields perpendicularly to the plane of a thin magnetic film. CONSTITUTION:Striped magnetic domains 6 and the circumferential magnetic wall 8 are formed in a thin magnetic garnet film 4. A ferromagnetic material layer 12 of a thin layer consisting of CoPt, etc., is formed on the surface of the thin magnetic film 4. Said layer has the axis of easy magnetization in a direction (x) and is magnetized clockwise. Both end edges in a direction (y) have the symmetrical saw tooth shape and superpose partially on the magnetic wall 8. The magnetization in the magnetic wall of the magnetic wall parts 8a, 8b is rotated clockwise by a gyro effect when the impulsive magnetic fields are impressed downward to the thin magnetic film 4 in the film direction thereof. The Bloch line pair is then moved by one to the adjacent potential wall toward the right along the magnetic wall part 8a and to the left along the magnetic wall part 8b.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a block line memory, and particularly to information KIIT.
Concerning the transfer method of Holline, a professional who has achieved 4Ii rankings. Bronholline memory is a memory that can record information at extremely high density and can be applied to various electronic devices.

[Prior Art] At present, memories such as external memory for computers, memory for electronic files, and memory for still image files include magnetic tape, Winchester disk, floppy disk, optical disk, magneto-optical disk, magnetic bubble memory, etc. Various types of memory devices are used. Among these memory devices, other than the magnetic bubble memory, it is necessary to move the recording/reproducing head relative to the memory when recording or reproducing information. That is,
With such relative movement of the head, the head records an information string fixedly on the information track or reproduces the information string fixedly recorded on the information track.

However, in recent years, as there has been a demand for increasingly higher recording densities, tracking control to make the head accurately follow the information track has become more complex, and the quality of recorded and reproduced signals may deteriorate due to insufficient control. The quality of recorded and reproduced signals may deteriorate due to vibrations in the head moving mechanism and dust on the surface of the memory.Furthermore, in the case of memories that are recorded and reproduced while in contact with a magnetic tape, etc. In the case of a memory that performs recording and reproduction without contact with the head, such as an optical disk, focusing control is required for focusing, and because this control is insufficient, the quality of the recording and reproduction signal may deteriorate. There is a problem of a decline.

On the other hand, magnetic bubble memory can record information at a predetermined position and transfer the recorded information, and can reproduce information at a predetermined position while transferring the information. Since no relative movement is required, it is believed that the above-mentioned problems will not occur even when the recording density is increased, and high reliability can be achieved.

However, magnetic bubble memory uses circular magnetic domains (bubbles), which are generated by applying a magnetic field to a magnetic thin film such as a magnetic garnet film, whose axis of easy magnetization is perpendicular to the film surface, as information bits. Minimum bubble (diameter 0.3u) limited by material properties of garnet film
Even when using Lm), several tens of Mbit/c are recorded. ! :
However, it is difficult to further increase the density.

Therefore, Bloch line memory has recently been attracting attention as a memory having a recording density that exceeds the recording density limit of the above-mentioned magnetic bubble memory. This blog line memory is
Because it uses a pair of Neel domain wall structures (Bloch lines) sandwiched between Bloch domain wall structures that exist around the magnetic domains generated in the magnetic gJ film as information bits, the recording density is nearly two orders of magnitude higher than that of the above-mentioned magnetic bubble memory. It is possible to improve the sophistication of For example, when using a garnet film with a bubble diameter of 0.5 uLm, it is possible to achieve a recording density of 1.6 Gbit/crn' [[Nikkei Electronics J, August 15, 1983, p. 141-167]
reference].

FIG. 11 shows a schematic perspective view of an example of the magnetic structure constituting the Bloch line memory.

In the figure, 2 is a substrate made of non-magnetic garnet such as GGG or NdGG, and a magnetic garnet film 4 is provided on the substrate. The film can be formed by, for example, a liquid phase epitaxial growth method (LPE method),
Its thickness is, for example, about 5 lumens. Reference numeral 6 denotes a striped magnetic domain formed in a magnetic Gurney thin layer 4, and a domain wall 8 is formed as an inner and outer boundary region of the magnetic domain.

The width of the striped magnetic domain 6 is, for example, about 54 m, and the length is, for example, about 100 gm. Further, the thickness of the domain wall 8 is, for example, about 0.5 Bm. As shown by the arrow, the direction of magnetization within the magnetic domain 6 is upward;
On the other hand, outside the magnetic domain 6, the direction of magnetization is downward.

The direction of magnetization within the domain wall 8 gradually rotates from the inner surface (that is, the surface facing the magnetic domain 6) to the outer surface in a twisted manner.

The direction of this rotation is opposite on both sides of the bloch line IO, which is present in the vertical direction in the domain wall 6, as a boundary. 1st
In FIG. 1, the direction of magnetization at the center of the domain wall 8 in the thickness direction is indicated by an arrow, and the direction of magnetization at the Bloch line 10 is similarly indicated.

Note that a downward bias magnetic field HB is applied to the above-described magnetic structure from the outside.

As shown in the figure, the Blotsuho line 10 has a direction of magnetization,
There are two different types, and the presence or absence of a pair of these bloch lines corresponds to information "l" and ° "0". The Bloch line pairs exist at regular positions in the domain wall 8, that is, at any one of the potential wells. Further, each Bloch line pair is sequentially transferred to an adjacent potential well by applying a pulsed magnetic field perpendicular to the substrate surface. In this way, it is possible to record information in the Blotsho line memory (writing Blotsho line pairs to the domain wall 8) and to reproduce information recorded in the Blotsho line memory (
51 reading of the Bloch line pairs in the wall 8 can be carried out at respective predetermined positions while the Bloch line pairs are being transferred within the domain wall 8. The above information can be recorded and reproduced by applying a pulsed magnetic field of a predetermined strength perpendicular to the substrate surface to a predetermined portion.
Although not shown in the figure, conductive patterns for pulsed current application are formed on the surface of the magnetic thin film 11514 at predetermined positional relationships with respect to the striped magnetic domains 6 as means for applying a pulsed magnetic field for recording and reproducing. .

[Problems to be solved by the invention] However, in the above-mentioned block line memory,
The potential wells for the Bloch line pairs are formed, for example, by providing a regular pattern on the surface of the magnetic thin film so as to cross the domain walls.

FIG. 12 is a partial plan view of a Bloch line memory showing an example of such a pattern.

In the figure, on the surface of the magnetic thin film 4, a large number of line-shaped patterns 9 extending in a direction across the striped magnetic domains 6 are provided in parallel. The pattern is, for example, Cr, AI
, Au, Ti, etc., and its width is, for example, 0.
．． It is about 5 gm, and the arrangement pitch is, for example, about 1 pLm. Due to the distortion caused by the formation of the patterned conductor layer, the potential wells within the domain wall 8 can be arranged regularly and periodically. Further, as the pattern 9, in addition to the conductor layer, for example, a magnetic layer, or a material in which ions such as H ions, He ions, Ne ions, etc. are implanted in the pattern shape near the surface of the magnetic thin film 4 is used. You can also do that. Each potential well formed by these patterns is symmetrical with respect to the Bloch line transfer direction.

By the way, as mentioned above, the Bloch line transfer is performed by applying a pulsed magnetic field perpendicular to the film surface of the magnetic thin film 4, and using the precession of the magnetization generated by this to move the Bloch line to an adjacent potential well. It is done by letting However, in the case of a symmetrical potential well like the one described above, it is not possible to stably move it in a specific direction by using a simple rectangular pulsed magnetic field as the pulsed magnetic field. As the pulsed magnetic field Hp for Bloch line transfer, a pulsed magnetic field having a sufficiently larger fall time than rise time was used, thereby ensuring irreversible transfer in a specific direction.

For this reason, the electrical circuit for generating a pulsed magnetic field is more complicated than in the case of generating a rectangular pulsed magnetic field, and since the fall time is long, it is difficult to improve the transfer speed, and the power consumption also increases. There was a point.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems in the information transfer of the conventional blowline memory, and to realize stable, high-speed, and good blowline transfer with a simple configuration.

[Means for Solving the Problems] According to the present invention, in order to achieve the above-mentioned objects, there is provided a block for recording information using blotting lines in domain walls formed around magnetic domains in a magnetic thin film. A method for transferring Blotsho lines, which are information, within a magnetic domain wall in a Lotsho line memory, which is characterized by forming a directional periodic potential along the domain wall and applying a pulsed magnetic field perpendicular to the film surface of the magnetic thin film. A method for transferring information in a block line memory is provided.

[Example] Hereinafter, specific examples of the present invention will be described with reference to the drawings.

FIG. 1(a) is a partial plan view of a Bloch line memory for explaining the first embodiment of the method of the present invention, and FIG. An example is an example in which the potential is formed based on the application of a periodic in-plane magnetic field oriented parallel to the film surface of the film and along the domain wall.

In FIG. 1, 2 is a non-magnetic garnet substrate, and 4 is a non-magnetic garnet substrate.
is a magnetic garnet thin film. Magnetic domains 6 having a striped planar shape are formed in the magnetic garnet thin film. 8 is a domain wall around the striped magnetic domain 6.

The direction of magnetization within the striped magnetic domain 6 is upward, and the direction of magnetization in the portion of the magnetic F1 film 4 outside the magnetic domain is downward. Further, a downward bias magnetic field is applied from the outside.

A ferromagnetic material Ifj12 is formed on the surface of the magnetic thin film W24 in a region substantially corresponding to the stripe magnetic domains 6. The ferromagnetic layer is made of a thin layer such as Coat, and its thickness is, for example, about O.luLm. The ferromagnetic layer 12
has an axis of easy magnetization in the X direction and is magnetized to the right. As shown in FIG. 1(a), the X of the ferromagnetic layer 12
Both end edges in terms of direction have a 5IIIi shape that is symmetrical to each other, and partially overlap the domain wall 8 . The arrangement pitch of the sawtooth-shaped teeth at the edge of the ferromagnetic layer 12 is, for example, about 4 JLm. The ferromagnetic layer 12 having such a planar shape can be formed by, for example, ion milling.

FIGS. 2(a) and 2(b) are schematic plan views showing pairs of Bloch lines within a domain wall.

FIG. 2(a) shows a pair of brochure lines in one domain wall portion 8a shown in FIG. 1(a), and FIG.
) shows the Blotsho line pair in the other domain wall portion 8b. As shown in FIG. In this case, the part between the two blow 2 hole lines 10 is facing leftward. As shown in FIG. 2(b), the domain wall magnetization in the domain wall portion 8b is directed to the left in areas other than the Bloch line pair, and is opposite in the area between the two Bloch lines 10 in the Bloch line pair area. facing to the right.

FIGS. 3 and 4 are diagrams for explaining the magnetic properties within the domain wall in this example.

FIG. 3(a) shows the domain wall portion 8 in FIG. 1(a) above.
It shows the partial plane shape along a.

FIG. 3(b) is a graph showing the in-plane magnetic field component at the position within the domain wall corresponding to FIG. 3(a), with the rightward direction being positive along the domain wall direction, and C) is a graph showing the distribution of force required for Blochlain versus movement.

As shown in FIG. 3(b), the ferromagnetic layer 12 is magnetized in the X direction, and the planar shape of the edge of the ferromagnetic layer is a directional sawtooth shape on the domain wall portion 8a. The in-plane magnetic field component H2 in the X direction, which is generated based on a certain fact, has an fMIJiI-like distribution with periodicity corresponding to the uneven shape of the edge of the ferromagnetic layer 12. As shown in FIG. 2(a) above, in the domain wall portion 8a, the direction of domain wall magnetization between the two Blotsho lines IO of the Blotsho line pair is leftward, so the negative portion of H2 (see FIG. 3(b) The brochure pair is stably located at a point (indicated by 18), which becomes a potential well.

In this embodiment, magnetic 8[When a pulsed magnetic field is applied downward in the thickness direction of the film 4, the domain wall portion 8 is
The magnetization within the domain wall at point a rotates around the makkei in Fig. 2(a),
As a result, the blow and holine pairs are moved rightward along the domain wall portion 8a (at this time, the blow and holine pairs are moved rightward along the domain wall portion 8a).
is also caused to move downward in the y direction as a whole), and the magnitude of the driving force for the movement of the Bloch line pair due to this gyro effect is (4π/γ)Mvwall, where γ is the gyro constant and M is the domain wall. 8
is the magnitude of saturation magnetization, and vwa□1 is the domain wall movement speed. In the part where the Brochure line exists, the domain wall movement speed is vwa l l''αγfl−He, and therefore the magnitude of the above driving force is 4πf1Mα·He, where le is a parameter in the domain wall, and α is the Gilpert , and He is the damping constant of z acting on the domain wall.
is the effective magnetic field in the direction (including the pulsed magnetic field Hp and the change in demagnetizing field due to domain wall movement).

On the other hand, based on the existence of the above-mentioned in-plane magnetic field component H2,
Rotation of magnetization within the domain wall due to the above-mentioned gyro effect is suppressed. The magnitude of this suppressing force is 2 πn M 11) (Jl).

Therefore, the driving force F for moving the Bloch line to the right in the domain wall portion 8a is Fd=4tc1Ma*He-2πl1M*H.

=2π8M to a (2He Hx / a), and since α is smaller than l, H, is extremely effective in controlling pro7 holine movement. That is, at a position where Hx is positive, an extra force is required to move the Bloch line pair compared to the case where there is no in-plane magnetic field component. Assuming that this force is F', F' has a distribution as shown in FIG. 3(C). In this figure, a force directed to the right is defined as positive, and in order to move the Protubo line pair to the right, a driving force as shown by the solid line is required, and in order to move the Protubo line pair to the left, the driving force shown by the solid line is required. A driving force as shown by the dotted line with opposite polarity is required.

FIG. 4(a) is the domain wall portion 8 in FIG. 1(a) above.
It shows the partial plane shape along b, and (b) in Fig. 4
is a graph showing the in-plane magnetic field component along the direction of the domain wall at the position within the domain wall corresponding to FIG. 4(a), with the rightward direction being positive; FIG. It is a graph showing the distribution of the force required for this purpose. These are the same figures as FIGS. 3(a) to 3(c) above.

As shown in FIG. 2(b) above, in the domain wall portion 8b, the direction of domain wall magnetization between the two Blotsho lines 10 of the Blotsho line pair is rightward. ), the pair of brochure lines is stably located at 20), which becomes a potential well.

When a pulsed magnetic field is applied downward in the film thickness direction of the magnetic J film 4, the magnetization within the domain wall in the domain wall portion 8b rotates clockwise in FIG. 2(b) in the same manner as explained with reference to FIG. As a result, the Bloch line pair is moved to the left along the domain wall portion 8b (at this time, the domain wall portion 8b
is also moved as a whole in the y direction in the -L direction).

In the domain wall portion 8b, when H is negative, extra force is required to move the Bloch line pair compared to when there is no in-plane magnetic field component. Letting this force be F', F' has a distribution as shown in FIG. 4(C). In this figure, a force directed to the left is defined as positive, and in order to move the pair of Blotsuho lines to the left, a driving force as shown by the solid line is required, and to move the pair of Blotsuho lines to the right, the driving force is the opposite of that for the leftward direction. A driving force as shown by the polar dotted line is required.

FIG. 5 is a diagram showing the above-mentioned pulsed magnetic field and the driving force for moving the pair of Bloch lines generated as a result of its application.

FIG. 5(a) shows a waveform diagram of the pulsed magnetic field HP, which is a substantially rectangular pulsed magnetic field with a difficult rise time and fall time (for example, rise time t = 50n).
sec, peak time t = 1r
poons
ec , fall time tf = 50 nsec). Based on the fact that He changes with time due to the application of this pulsed magnetic field, a positive force (indicated by 22 in Fig. 5(b)) is generated at the rise time. a negative force (indicated by 24 in Fig. 5(b))
occurs. The driving force 22 drives the Bloch line pair rightward in the domain wall portion 8a, and drives the Bloch line pair leftward in the domain wall portion 8b. On the other hand, the driving force 24 drives the Bloch line pair leftward in the domain wall portion 8a, and drives the Bloch line pair rightward in the domain wall portion 8b.

Therefore, as the driving force 22, FIG. 3(C) and FIG. 4(
By determining the waveform of the pulsed magnetic field so that a driving force having a larger peak value than the force shown by the solid line in C) is generated, the magnetic domain wall portion 8a increases as the pulsed magnetic field rises.
Then, the Bloch line pair moves to the right over the potential wall to the adjacent potential well, and at the domain wall portion 8b, the Bloch line pair moves to the left over the potential wall to the adjacent potential well.

As the pulse magnetic field falls, the blow line pair receives a leftward force in the domain wall portion 8a due to the driving force 24, and the blow 2 hole pair receives a rightward force in the domain wall portion 8b, but in this case, it tries to move. Since the potential wall in the direction exists over a long distance, the driving force 24 disappears before the Bloch line pair can cross the potential wall, and in the end, the Bloch line pair cannot move to the original potential well adjacent to it. Thus, the result is that the Bloch line pair has moved clockwise by one potential well.

In the above embodiment, the periodic uneven shape of the edge of the magnetic layer formed on the surface of the magnetic thin film has a sawtooth shape, but in the present invention, the uneven shape has a directionality. Any other suitable shape may be used as long as it has a shape.

Furthermore, in the present invention, it is also possible to form the magnetic layer so as to correspond to regions other than the striped magnetic domains.

FIG. 6(a) is a partial plan view of a Bloch line memory for explaining a second embodiment of the method of the present invention, and FIG. 6(b) is a sectional view taken along line B--B. In FIG. 6, the same members as in FIG. This is an example in which a magnetic field is formed based on the application of a directional periodic in-plane magnetic field parallel to a magnetic thin film surface and along a domain wall.

In FIG. 6, a downward bias magnetic field is applied from the outside. Further, on the surface of the magnetic thin film 4, a large number of 1+I l 6 are formed at predetermined intervals so as to cross the domain wall 8. As shown in FIG. 6(b), B of the groove 16
The cross-sectional shape in the −B direction has a sawtooth shape. Above groove 1
The depth of the grooves 6 is, for example, about 2 m, and the arrangement pitch of the grooves is, for example, about 4 μm. IXIt16 like this
can be formed, for example, by ion milling.

As shown in FIG. 6(a), opposing portions 8 of the domain wall 8
The planar shapes of a and 8b are not linear in the B-B direction,
It has a meandering shape at the same pitch as the arrangement pitch of the grooves 16. This is because the surface of the magnetic thin film 1 and 4 is uneven, which causes a distribution in the components of the demagnetizing field in the film thickness direction (two directions). The domain wall 8 is displaced so that the width becomes wider, thereby maintaining an equilibrium state.

In this embodiment, the Bloch line pairs within the domain wall are in the same state as shown in FIGS. 2(a) and 2(b) above.

FIG. 7 and FIG. 8 are diagrams for explaining the magnetic properties within the domain wall in this example.

FIG. 7(a) is the domain wall portion 8 in FIG. 6(a) above.
It shows the cross-sectional shape of the domain wall along a, and (b
) is a graph showing the in-plane magnetic field component along the direction of the domain wall at the position within the domain wall corresponding to FIG. 7(k), with the rightward direction being positive; FIG. It is a graph showing the distribution of force required for.

As shown in FIG. 7(b), the in-plane magnetic field component H0 in the X direction generated due to the uneven surface of the magnetic thin film 4 has a sawtooth shape with an irregularity corresponding to the uneven shape of the surface of the magnetic thin film 4. has a distribution of As shown in FIG. 2(a) above, in the domain wall portion 8a, the direction of domain wall magnetization between the two Blotsho lines 10 of the Blotsho line pair is to the left.
The Bloch line pair is stably located in the negative part of Hx (indicated by 18 in FIG. 7(b)), and this becomes a potential well.

In this embodiment, when a pulsed magnetic field is applied downward in the thickness direction of the magnetic thin film 4, the domain wall portion 8a is caused by the gyroscopic effect.
The magnetization within the domain wall rotates clockwise in FIG. (forced to move downward).

In this embodiment as well, as in the first embodiment, the driving force Fd for moving the Bloch line to the right in the domain wall portion 8a is F = 2π8M a (2He Hx / a )
Since α is smaller than l, H is extremely effective in controlling the movement of the Bloch line. That is, at a position where H2 is positive, an extra force is required to move the Bloch line pair compared to the case where there is no in-plane magnetic field component. Letting this force be F', F' has a distribution as shown in FIG. 7(C).

In this figure, a force directed to the right is considered positive, and in order to move the pair of Bloch lines to the right, a driving force as shown by the solid line is required. A driving force as shown by the polar dotted line is required.

FIG. 8(a) is the domain wall portion 8 in FIG. 6(a) above.
It shows the cross-sectional shape of the domain wall along b.
) is a graph showing the in-plane magnetic field component along the direction of the domain wall at the internal position l of the domain wall corresponding to FIG. 8(a), with the right direction being positive. It is a graph showing the distribution of force required for movement. These are the same views as FIGS. 7(a) to (C) above.

As shown in FIG. 2(b) above, in the domain wall portion 8b, the direction of domain wall magnetization between the two blow lines of the Bloch line pair and the hole line 10 is rightward, so the positive portion of HJI (see FIG. In b), the pair of brochure lines is stably located at 20, which becomes a potential well.

When a pulsed magnetic field is applied downward in the thickness direction of the magnetic thin film 4, the magnetization within the domain wall in the domain wall portion 8b rotates clockwise in FIG. 2(b) in the same manner as explained with reference to FIG. As a result, the Bloch line pair is moved to the left along the domain wall portion 8b (at this time, the domain wall portion 8b
is also caused to move upward in the X direction as a whole).

In the domain wall portion 8b, when H2 is negative, an extra force is required to move the blow hole pair compared to when there is no in-plane magnetic field component. If this force is F', then the F
' has a distribution as shown in FIG. 8(C). In this figure, a force directed to the left is defined as positive, and in order to move the pair of Blotsuho lines to the left, a driving force as shown by the solid line is required, and to move the pair of Blotsuho lines to the right, the driving force is the opposite of that for the leftward direction. A driving force as shown by the polar dotted line is required.

In this embodiment as well, the waveform of the pulsed magnetic field and the driving force for moving the pair of Bloch lines generated upon application of the pulsed magnetic field are as shown in FIG. 5 above.

The driving force 22 drives the Bloch line pair rightward in the domain wall portion 8a, and drives the Bloch line pair leftward in the domain wall portion 8b. On the other hand, the driving force 24 drives the Bloch line pair leftward in the domain wall portion 8a, and drives the Bloch line pair rightward in the domain wall portion 8b.

Therefore, as the driving force 22, FIG. 7(C) and FIG. 8(
By determining the waveform of the pulsed magnetic field so that a driving force having a larger peak value than the force shown by the solid line in C) is generated, the magnetic domain wall portion 8a increases as the pulsed magnetic field rises.
In this case, the Bloch line pair moves to the right over the potential wall to the adjacent potential well, and at the domain wall portion 8b, the Bloch line pair moves to the left over the potential wall to the adjacent potential well.

As the pulse magnetic field falls, the blow 2 hole pair receives a leftward force in the domain wall portion 8a due to the driving force 24, and the blow 2 hole pair receives a rightward force in the domain wall portion 8b, but in this case, it will not move. Since the potential wall in the direction of exists over a long distance,
The driving force 24 disappears before the Bloch line pair crosses the potential wall, and in the end, the Bloch line pair cannot move to the adjacent original potential well.Thus, as a result, the Bloch line pair only covers one potential well. It will move clockwise.

In the embodiment described above, a case is shown in which the periodic uneven shape on the surface of the magnetic Pi film is a sawtooth shape, but in the present invention, the uneven shape can be any other suitable shape as long as it has directionality. It may be in the shape of

FIG. 9(a) is a partial plan view of a block line memory for explaining the third embodiment of the method of the present invention, and FIG. 9(b) and FIG. 9(C) are respectively B- They are a B sectional view and a CC sectional view. In FIG. 9, the same members as in FIG. This is an example in which a different magnetic property region is formed with directionality along the domain wall.

In FIG. 9, a downward bias magnetic field is applied from the outside. Further, near the surface of the magnetic thin film 4, Iiii
Sawtooth-shaped ion implantation regions 4a and 4b are formed at predetermined intervals across the wall 8. Figure 9(b), (
As shown in c), each ion implantation region 4a, 4b has a depth distribution that continuously changes in the direction of the domain wall 8 (i.e., B-B direction, C-C direction). The direction of this change is opposite between the ion implantation regions 4a and 4b. Ions to be implanted include, for example, H ions, He
Ions, Ne ions, and the like having a relatively small ionic radius are preferable, and these ions are implanted at about aKeV to several + KeV to form ion implantation regions 4a and 4b with a maximum depth of about 3 gm near the surface of the magnetic thin film 4. Ion implantation region 4a.

The shape of 4b can be made into a desired shape by using an appropriate mask during implantation, but for example, a width of 2g can be obtained.
The arrangement pitch is about 4 μm. Further, the depth of ion implantation can be controlled by focusing the ions into a beam, changing the implantation energy, and scanning the beam by gradually shifting the distance l.

FIG. 10 is a diagram for explaining the magnetic properties within the domain wall in this example.

Figure m10 (7) (a) is the same figure as Figure 9 (b) above;
) is a graph showing the magnetic anisotropy at the position within the domain wall corresponding to FIG. FIG.

E7'SI 0 As shown in Figure (b), the magnetic properties change in the ion implantation region 4a and the positions near it in accordance with the ion implantation depth.

In the vicinity of the ion implantation edge of the ion implantation region 4a (indicated by 12' in FIG. 10(b)), due to the symmetry of lattice strain, the direction along the edge side surface, that is, the domain wall 8
The direction perpendicular to is the axis of easy magnetization. Therefore, the Bloch line can be stably located here, that is, this becomes a potential well with directionality.

By the way, the moving speed of the Bloch line when the pulsed magnetic field Hp is applied in the direction perpendicular to the film surface of the magnetic source W24 is v B L = y e Hp A / 2 πM
It is expressed as s2. Here, γ is the gyro constant,
A is the exchange interaction constant and M s 41 saturation magnetization. It is known that A is significantly reduced by the above-described ion implantation, and when the average value of the moving speed of the Bloch line in the film thickness direction is determined from the above equation, the result is as shown in FIG. 10(C). This means that there is an asymmetry in the ease of movement of the Bloch line, and the movement in the direction of arrow X in the figure is better than the movement in the opposite direction.

Therefore, a substantially rectangular vertical pulse magnetic field Hp as shown in FIG.
0nsec, peak time t = 20r
p
Onsec, fall time jf=lQOnsec), by appropriately setting the magnitude of the pulsed magnetic field, the Bloch line moves in the direction of arrow X, moves to the next stable position, and then There is no possibility of returning to the previous stable position in the opposite direction at the same time as the pulsed magnetic field disappears.

As shown in FIG. 9, since the ion implantation regions 4a and 4b have opposite directions, applying the same perpendicular pulse magnetic field causes the loop-shaped domain wall 8 to move in the direction of the arrow X in FIG. 9(a). The blotsuho line moves along it.

In the above embodiment, the ion implantation region, which is a different magnetic region, is given directionality by the ion implantation depth distribution, but in the present invention, the directionality of the ion implantation region is given by the implanted ion concentration distribution and the implanted ion species. It may be provided by distribution or the like.

[Effects of the Invention] According to the present invention as described above, in the Bloch line memory, the Bloch line can be reliably transferred in a specific direction by applying a simple rectangular pulse magnetic field, so the electric circuit is simple and easy to use. Furthermore, since the fall time is short, it is possible to improve the transfer speed and shorten the access time.
Furthermore, the power consumption is reduced, and thus it is possible to realize a block line memory that operates stably and at high speed with an IPI-width configuration.

[Brief explanation of drawings]

11K(a) is a partial plan view of the Bloch line memory, and FIG. 1(b) is a sectional view thereof taken along line BB. FIGS. 2(a) and 2(b) are diagrams showing Bloch line pairs within the domain wall. FIGS. 3 and 4 are diagrams for explaining magnetic properties within a domain wall. FIG. 2 is a diagram for explaining the magnetic properties of FIG. 5 is a diagram showing the waveform of a pulsed magnetic field and the driving force for moving a pair of Bloch lines generated with the application of the magnetic field. FIG. 6(a) is a partial plan view of the Bloch line memory, and FIG. 6(b) is a sectional view taken along line BB. FIG. 7 and FIG. 8 are diagrams for explaining the magnetic properties within the domain wall. FIG. 9(a) is a partial plan view of the block line memory, and FIG. 9(b) and FIG. 9(C) are respectively its B-
They are a B sectional view and a CC sectional view. FIG. 10 is a diagram for explaining magnetic properties within a domain wall. FIG. 11 is a schematic perspective view of the magnetic structure constituting the Bloch line memory. FIG. 12 is a partial plan view of the Bloch line memory. FIG. 13 is a diagram showing the waveform of the pulsed magnetic field. 22 substrates, 4: magnetic thin film. 4a, 4b: ion implantation region, 6: magnetic domain, 8: domain wall, lO: brochure line, 12 two ferromagnetic layers, 16 two grooves. Agent Patent Attorney Seki Yamashita Figure 3 Figure 4 Figure 7 (G) Figure 2 (b Figure 2 (C Figure 1 O〈:::== × Figure 11 Figure 12 Figure 13 figure

Claims (7)

[Claims] (1) In a method of transferring Bloch lines, which are information, within a domain wall in a Bloch line memory that records information using Bloch lines within a domain wall formed around a magnetic domain in a magnetic thin film, the direction along the domain wall is A Bloch line memory information transfer method is characterized by forming a periodic potential with a magnetic property and applying a pulsed magnetic field perpendicular to the film surface of a magnetic thin film. (2) The information transfer method of the Bloch line memory according to claim 1, wherein the potential is formed based on the application of a periodic in-plane magnetic field having directionality parallel to the film surface of the magnetic thin film and along the domain wall. . (3) The information transfer method of the Bloch line memory according to claim 2, wherein the periodic in-plane magnetic field is obtained based on the unevenness in the planar shape of the edge of the horizontally magnetized magnetic layer formed on the magnetic thin film. . (4) The information transfer method of a Bloch line memory according to claim 2, wherein the periodic in-plane magnetic field is obtained based on the uneven shape of the surface of the magnetic thin film including the domain wall portion. (5) The Bloch line memory according to claim 1, wherein the potential is formed based on forming a region of different magnetic properties with directionality along the domain wall near the surface of the magnetic thin film in the domain wall portion. information transfer method. (6) The information transfer method of a Bloch line memory according to claim 5, wherein the different magnetic properties region is formed by ion implantation. (7) The information transfer method of a Bloch line memory according to claim 1, wherein the pulsed magnetic field is a substantially square-wave pulsed magnetic field.