Magnetic memory device and magnetic memory apparatus

1. A magnetic memory device comprising:

a spin orbit torque (SOT) source configured to generate SOT; and

a magnetic fine wire having an end contacting a main surface of the SOT source,

wherein a direction of SOT generated by the SOT source is perpendicular to a direction in which the magnetic fine wire extends,

a plurality of magnetic domains, in the magnetic fine wire, each of the plurality of magnetic domains corresponding to a uniform magnetic direction extending parallel to or antiparallel to the direction in which the magnetic fine wire extends, and

the magnetic fine wire is configured to store a plurality of bits, each of the plurality of bits corresponding to respective ones of the plurality of magnetic domains, and each of the plurality of magnetic domains separated by a magnetic domain wall extending perpendicular to the extension direction of the magnetic fine wire.

2. The magnetic memory device of claim 1 , wherein the SOT source comprises a non-magnetic material.

3. The magnetic memory device of claim 1 , wherein the SOT source comprises a topological insulator.

4. The magnetic memory device of claim 1 , wherein the SOT source comprises a ferromagnetic material.

5. The magnetic memory device of claim 1 , wherein the magnetic fine wire comprises a ferromagnetic metal.

6. The magnetic memory device of claim 1 , wherein the magnetic fine wire comprises at least one of a cobalt (Co)/nickel (Ni) multilayer, a CoNi-based alloy, a Co/palladium (Pd) multilayer, a CoPd alloy, a Co/Pt multilayer, a CoPt alloy, a terbium (Tb)/iron (Fe)Co multilayer, a TbFeCo alloy, a CoFe alloy, a CoFeB alloy, a Fe/Ni multilayer, or a FeNi alloy.

7. The magnetic memory device of claim 1 , further comprising:

a first electrode and a second electrode, the first electrode and the second electrode configured to flow a current to the SOT source in a direction perpendicular to a direction of the SOT; and

a third electrode configured to flow a current to the magnetic fine wire in a direction parallel with the direction in which the magnetic fine wire extends.

8. The magnetic memory device of claim 7 , further comprising:

an insulating layer stacked on another end of the magnetic fine wire; and

a fixed layer between the insulating layer and the third electrode.

9. The magnetic memory device of claim 7 , further comprising:

a non-magnetic metal layer stacked on the other end of the magnetic fine wire; and

a fixed layer stacked on the non-magnetic metal layer.

10. The magnetic memory device of claim 9 , wherein the fixed layer has perpendicular magnetic anisotropy.

11. The magnetic memory of claim 1 , wherein

a length of a one of the plurality of magnetic domains from a first one of the magnetic domain walls to a vertically neighboring second one of the magnetic domain walls corresponds to one of the plurality of bits as determined by a controller.

12. A magnetic memory apparatus comprising:

a spin orbit torque (SOT) source extending in a horizontal direction;

a first electrode at one end of the SOT source and a second electrode at another end of the SOT source;

a magnetic fine wire extending on the SOT source in a direction perpendicular to the horizontal direction;

at least one of an insulating layer or a non-magnetic metal layer, the insulating layer or the non-magnetic metal layer on an upper end of the magnetic fine wire;

a fixed layer on the insulating layer or the non-magnetic metal layer;

a third electrode on the fixed layer; and

controller circuitry electrically connected to the first electrode, the second electrode, and the third electrode, wherein

the controller circuitry is configured to move a magnetic domain in the magnetic fine wire upward by flowing a current between the first electrode and the third electrode.

13. The magnetic memory apparatus of claim 12 , wherein the controller circuitry is configured to form a magnetic domain in a lower portion of the magnetic fine wire by flowing a current between the first electrode and the second electrode in a direction corresponding to recorded information.

14. The magnetic memory apparatus of claim 12 , wherein the controller circuitry is configured to read a direction of magnetization of a magnetic domain at the upper end of the magnetic fine wire by applying a voltage between the first electrode and the third electrode and measuring a current flowing between the third electrode and the first electrode.

15. The magnetic memory apparatus of claim 12 , wherein the controller circuitry is configured to read a direction of magnetization of a magnetic domain at the upper end of the magnetic fine wire by flowing a current between the first electrode and the third electrode and measuring a voltage between the first electrode and the third electrode.

16. A magnetic memory apparatus comprising:

a spin orbit torque (SOT) source configured to generate SOT;

a magnetic fine wire on the SOT source;

a first electrode and a second electrode, the first electrode and the second electrode configured to flow a current to the SOT source in a direction perpendicular to a direction of the SOT;

a third electrode configured to flow a current to the magnetic fine wire in a direction parallel to a direction in which the magnetic fine wire extends; and

controller circuitry connected to the first electrode, the second electrode, and the third electrode,

wherein the controller circuitry is configured to flow a current between the first electrode and the third electrode during a magnetic domain moving operation.

17. The magnetic memory apparatus of claim 16 , wherein the controller circuitry is configured to flow a current between the first electrode and the second electrode in a direction corresponding to recorded information during a recording operation.

18. The magnetic memory apparatus of claim 16 , wherein the controller circuitry is configured to apply a voltage between the first electrode and the third electrode and to measure a current flowing between the third electrode and the first electrode during a read operation.

19. The magnetic memory apparatus of claim 16 , wherein the controller circuitry is configured to flow a current between the first electrode and the third electrode and to measure a voltage between the first electrode and the third electrode during a read operation.