JPS63108586A - Magnetic storing method - Google Patents

Abstract

PURPOSE:To stably read information by stretching a part of the peripheral magnetic domain wall at the end part of a stripe domain, locally applying a in-plane magnetic field and cutting off the domain in an area. CONSTITUTION:A pulse current is applied to a conductor pattern 7 and the end part of the stripe domain is guided to a reading part, and then, a Bloch line VBL4 is moved to an upper side wall once due to a gyroscopic force. A parallel current is applied to conductor patterns 10-12 and the in-plane magnetic field Hip is applied longitudinally so as to include a domain end part 3' to the end part of the stripe domain and the pulse current is applied to a conductor 13 or 7 to apply a pulse bias magnetic field of the same direction as a static bias magnetic field to the end part 3' and dynamically move leftward. The VBL is moved to the lower side wall according to the gyroscopic force Hip and trapped at the left side of the conductor pattern 10 in which the Hip is present. Mutually opposite and parallel pulse currents are applied to conductor patterns 8, 9 to apply a magnetic filed of a direction Hz to an area between 8, 9 and cut off the domain.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a storage method for a non-volatile ultra-high density solid state magnetic storage element.

(Prior Art) One of the most important parts in a device using this method is an information reading section. The magnetic memory element to which this method is applied includes information reading means and information writing means, and means for transferring the pair of Bloch lines (hereinafter referred to as VBL) within the Bloch domain wall. In such a magnetic memory element, a means for reading out information written in the striped domain domain walls in the form of VBL pairs is essential. Conventionally, when there are three VBLs 14 (a VBL pair that is data and a VBL that was previously at the tip) at the tip of the stripe domain, as shown in Figure 4, these three are held at the tip and gradually stretched. Among the three VBLs, an in-plane magnetic field is locally applied in the longitudinal direction of the stripe domain in the middle of the stretch, or in the region including the tip after being stretched.
Keep only the center one at the tip, move the other two to the side walls on both sides, and after separating the three, connect the tip and the other two Vs.
In the region between the position where the BL is held, the magnetization of the upper and lower side walls are cut parallel to each other, and the VBL is placed at the tip.
When there is only one tip, the VBL is moved to either side wall sandwiching the tip by the local in-plane magnetic field described above, and the tip is placed in a unichiral state so that it is not cut. (1986 IEICE Comprehensive National Conference (1)
986, 3) Lecture number 2289 Journal of the Japanese Society of Applied Magnetics 10
(1986) pp414-418. INTERMAG
'86 (1986) DD-05,) L However, this method requires that three VBLs are ultimately retained at the tip when the tip of the striped domain is stretched, so domain stretching is not possible. It is important to do this with good controllability. An error occurs if the following occurs: In other words, if the domain wall movement speed when stretching the tip is high, a gyroscopic force acts, and the VBL of the tip may temporarily move toward the side wall. Thereafter, the right one of the three VBLs returns to the tip due to the in-plane magnetic field applied along the longitudinal direction of the stripe domain over the entire chip to stabilize the VBL pairs in the information storage section. If we simply apply the above-mentioned local in-plane magnetic field to this state, the VBL at the tip will not necessarily move to the side wall opposite to the side wall where the remaining two VBLs exist, and the VBL will 3
Sometimes it is stabilized on the same side wall as the book.

In this case, although one VBL is placed at the tip, which is the intended purpose, it becomes impossible to discriminate whether or not the stripe domain tip is cut using the difference in whether or not there is any VBL placed.

This content will be explained using Fig. 4(a) to (O1) and Fig. 5(a) to (O). Apply a current to the conductor pattern 7 in the direction of the arrow to stretch it to the position.

At that time, unless the entire culm is stretched in a carefully controlled manner, the VBL pair, which is an information carrier existing at the tip 3 position (bit position) of the stripe domain before stretching, and the VBL originally existing at the tip will be Together, they may once move to the upper side wall due to the gyroscopic force, as shown in FIG. 4(a). After that, due to the interaction with the in-plane magnetic field HipO, which is applied in the longitudinal direction of the stripe domain to maintain the VBL pair of the information storage part over the entire chip, only one VBL at the right end becomes as shown in FIG. 4(b). Return to the tip. In this state, conductor patterns 10, 11.
When applying a parallel current to 12 and applying only the in-plane magnetic field H1p in the opposite direction to HipO to the region including the domain tip in the stretched domain part, the VBL at the tip is as shown in Figure 4 (
Move in the direction of arrow 15 in c) or in the direction of arrow 18 in (e). On the other hand, the two VBLs remaining on the upper side wall are also H.
They are separated by interaction with lp, and one moves in the 19 direction and the other in the 20 direction. If the VBL at the tip of the stripe domain moves in the direction of 18, it will collide with the VBL that has moved in the direction of 19, and a new VBL will be created as shown in Figure 4 (
A VBL pair indicated by 21 is created at O. In such a state, the sidewall magnetization of the region sandwiched between the cutting conductor patterns 8 and 9 at the domain tip becomes opposite to each other on the upper and lower sides, resulting in a striped domain tip, which will be explained later in FIG. Compared to the case where there is only one VBL in 3, there is no difference in the relative relationship between the upper and lower side wall magnetizations in the cutting region, and there is no difference in the cutting conditions. On the other hand, when Hlp is applied to the tip, the VB of the tip moves in the direction shown at 15 in Fig. 4(c).
L moves and the upper two VBLs are each 16.17
When the state shown in FIG. 4(d) is obtained, the upper and lower side wall magnetizations in the cutting region become parallel to each other, which is different from the state shown in FIG. 5(d). ing. At this time, there are three Vs at the tip 3 of the stripe domain.
When stretched with and without one BL, the difference is that if there are three VBLs in the same cutting magnetic field, they will be cut and a bubble will be formed, and if there is only one, they will not be cut and no bubbles will be formed. Can be done. Figure 5 shows 1 at the tip 3.
This is the case when there is a real VBL, that is, when the VBL pair has not been transferred to the tip 3. In this case, using the conventional method, VBL only moves to either the upper or lower sidewall, but the relative relationship between the upper and lower sidewall magnetizations of the cut portion remains unchanged, as shown in Figures 5(d) and (f). are antiparallel to each other. From the above, in this method, when a VBL pair is transferred to the tip 3, there is a high probability that an error will occur.

(Problem to be solved by the invention) In the conventional readout method, V
When there is a BL pair, it is necessary to precisely control the current waveform applied to 7 in advance so that it does not come off the three tips together with one VBL at the tip. This is because when the domain wall moves quickly, the VBL at the tip moves to the side wall due to the gyroscopic force. This may cause the problem shown in Figure 4 (O). It is important to find a means to solve this problem in order to improve reliability. In the present invention, a new method to solve this problem is introduced. present.

(Means for Solving the Problems) In the present invention, when reading information, the VBL at the tip of the stripe domain is not stretched while keeping it at that position, but in the process, the gyroscopic force generated at that time is used to make three lines in principle. The VBL 14 is once gathered on one side wall of the stretched domain as shown at 14'. Note that even if only the last one (one of the inner cloth ends of the three VBLs 14' on the upper side wall of the stretched domain in Fig. 4(a)) is left behind on the lower side wall, this new method does not cause any problems. After that, the in-plane magnetic field HipO applied to the entire chip moves only the rightmost VBL or the VBL left behind on the lower sidewall out of the three to the tip of the domain, and then in the local plane in the opposite direction to HipO. Almost simultaneously, when a magnetic field is applied to the stretched domain portion to include the tip, a pulse bias magnetic field is applied to the domain tip in the opposite direction to the stretching direction, and the VBL at the tip is removed from the tip by a gyroscopic force. Then, since this gyroscopic force is in the opposite direction to that when stretching the domain tip, the V at the tip
BL always moves toward the lower side wall. In this method, it is only necessary to prevent new VBL from being introduced to the tip during domain stretching, and considering that normally when the domain wall tip has velocity, a gyroscopic force acts on the VBL at the tip and the tip comes off. , the setting is easier compared to the conventional method. In the following, for the sake of simplicity, a case will be described in which all three VBLs have moved to the upper side wall due to the gyroscopic force during the stretching process of the domain tips.

(Function) In the present invention, the three Vs at the tip 3 of the minor loop
The process of stretching the tip of BL and then separating it into three pieces for the intended purpose will be explained. Figure 2 (a) shows the tip 3.
When a domain having three VBLs 14 is extended to the right by applying a current to the conductor pattern 7, the three VBLs come to 14' due to the gyroscopic force. Second
Figure (b) shows the in-plane magnetic field H that is applied to the entire chip by only the right one of the three VBLs on the stretched domain.
It shows a state in which it has moved to the tip of the domain due to ipO (in this case, it is added leftward). In this state, when an in-plane magnetic field in the opposite direction to HipO is applied in the longitudinal direction of the domain using the conductor patterns 10, 11, 12, a pulsed current is applied to the conductor pattern 13 or 7 almost at the same time, and the tip of the domain is ’ to the left dynamically, 3
The VBL existing at 14' moves toward the lower side wall due to the gyroscopic force, and a new VBL at the center of 14' moves to the tip.
moves to the tip due to Hlp. As a result, after domain stretching, the VBL 14 at the tip shown in FIG. 2(a) becomes 3.
It separates into books. In this state, two conductor patterns 8.9 are placed on the film surface, and a pulse current is applied to the conductor patterns so as to generate a magnetic field in the same direction as Hz in the area sandwiched between the conductor patterns. Then, the stripe domain is finally gJ-cleaved, resulting in two domains shown in FIG. 2(d). A negative VBL is injected into each domain by cutting. In other words, the negative VBL removed along with the bubble by cutting is replicated at the tip of the newly created stripe domain. In addition, in the method that does not use the wide conductor pattern shown in the existing method, by cutting off the current other than 10.12 of the conductor pattern for applying H1p when cutting the domain,
The probability that a horizontal Bloch line exists in the cut section can be reduced.

On the other hand, FIG. 3 shows the operation when there is no VBL pair at the tip 3 bit position of the minor loop. By stretching the domain tip, VBL4 moves to 4' as shown in FIG. 3(a). Thereafter, HipO moves to the tip 3'' as shown in FIG. 3(b). Then, 10
．． 11. When Hip is applied by the conductor pattern 12, a pulse bias magnetic field in the same direction as the bias magnetic field Hz is applied to the domain tip 3' by the conductor pattern 13 or 7 at the same time, dynamically moving the tip 3' to the left. When pressed, the VBL at the tip moves to the lower side wall, as shown in Figure 3 (C
) is obtained. In this state, the same pulsed magnetic field as in FIG. 2 is applied to the domain by the conductor patterns 8 and 9. In this case, the directions of magnetization at the centers of the upper and lower side walls are opposite to each other in the region between 8 and 9, so that they are not cut (FIG. 3(d)). The above is a mechanism for converting and reading information stored in the form of the presence or absence of VBL pairs in the striped domain domain wall soil into the presence or absence of bubbles in the present invention.

As shown in Japanese Patent Application No. 60-089321, the VBL pairs are erased by separating the three VBLs, cutting off the current in the conductor patterns 10 and 11 for applying H1p other than 12, and
After collecting all BL on the right side of conductor pattern 9,
All you have to do is cut the domain at the area between.

(Example) The content of the present invention will be explained using an example. FIG. 1 shows the basic configuration of a VBL pair readout section formed at the tip of a stripe domain. 3 is the tip of the stripe domain, and VBL4 at the tip is already included in the initial state of the storage domain. Reference numeral 7 denotes a conductor pattern used to stretch the tip of the stripe domain when reading the VBL pair.

10, 11, and 12 are conductor patterns for generating a local in-plane magnetic field in the longitudinal direction of the domain so as to include the tip 3' at the tip of the stripe domain. 8 and 9 are conductor patterns for cutting the domain tip. 13 is a conductor pattern that applies a pulse bias magnetic field to the domain tip. Next, the operation will be explained. First, a pulse current is applied to the conductor pattern 7 to guide the stripe domain tip to the readout section. Then, in this case, the VBL 14 moves to the -up side wall due to the gyroscopic force. Thereafter, it is stabilized at the tip 3' by interaction with HipO.

After that, a parallel current is applied to the conductor patterns 10, 11.
In this case, the in-plane magnetic field H is directed to the right in the longitudinal direction so as to include
1p, a pulse current is applied to the conductor pattern 13 or 7 at the same time, a pulse bias magnetic field in the same direction as the static bias magnetic field for stabilizing the stripe domain is applied to the tip 3', and the stripe domain is dynamically moved to the left. The accompanying gyroscopic force and Hlp move VBL to the lower side wall and trap it on the left side of the conductor button 10 where Hlp is present, and then apply pulse currents antiparallel to each other to the conductor pattern 8°9. A pulsed magnetic field in the same direction as Hz is applied to the region sandwiched by 8 and 9 to cut the domain.

(Effects of the Invention) According to the present invention, a stable information readout method has been established in a Bloch line memory that uses striped domain domain walls as information storage parts, and is more operable than the conventional method of simply applying an in-plane magnetic field to the tips of striped domains. has been stabilized.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the configuration of a VBL pair readout section in the present invention. FIG. 2 is a diagram showing a read process when there is a VBL pair in the present invention. FIG. 3 is a diagram showing a read process when there is no VBL pair. FIG. 4 is a diagram showing error modes that may occur when there is a VBL pair in the conventional method. FIG. 5 is a diagram showing a read process when there is no VBL pair in the conventional method. 1. Striped domain, 2. Domain wall, 3. Domain tip, 3′, domain tip after stretching, 4°VB
L, 5. Magnetization on the center line of the domain wall, 6. Magnetization within the domain, 7. Conductor pattern for domain stretching, 8, 9° conductor pattern for cutting domains, 10, 11, 12. Conductor pattern for applying in-plane magnetic field, 13. A conductor pattern that provides a magnetic field that dynamically moves the stretched domain tip,
14.14', VBL pair and v pre-existing at the tip
3 BL Kaishoni (7) VBL, 15, 16
,17,18°19.20. The direction in which each VBL moves due to the application of Hlp, Figure 1 Hip. Figure 2 (a) (d) Hip Figure 3 □Hip Hip Figure 4 Mlp ilp

Claims (1)

[Claims] A Bloch domain wall at the boundary of a swipe domain existing in a ferromagnetic (including ferrimagnetic) film that has information reading means, information writing means, and information storage means and whose easy magnetization direction is perpendicular to the film surface. A magnetic memory element using the stripe domain in the ferromagnetic film, the device having means for transferring a pair of two adjacent vertical Bloch lines (hereinafter referred to as VBL) formed inside the Bloch domain wall, and using the stripe domain in the ferromagnetic film. In this method, a part of the outer domain wall at the tip of the stripe domain is stretched, a local in-plane magnetic field is applied to the tip of the stretched stripe domain in the longitudinal direction of the stripe domain, and almost simultaneously, the direction in which the domain tip is stretched is A magnetic storage method characterized in that, after pushing in the opposite direction, a stripe domain is cut in a region to which this local in-plane magnetic field is applied.