MAGNETIC MEMORY DEVICE USING IN-PLANE CURRENT AND ELECTRIC FIELD

• US 20150236071A1
• Filed: 04/22/2013
• Published: 08/20/2015
• Est. Priority Date: 09/21/2012
• Status: Abandoned Application

• Current Assignee: Korea University Research and Business Foundation
• Original Assignee: Korea University Research and Business Foundation
• Inventors: Lee, Kyung-Jin, Lee, Seo-Won
• Application Number:
  US14/428,947
• Publication Number:
  US 20150236071A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G11C 11/161 details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell
• CPC Class Codes: G11C 11/1675 Writing or programming circuits or methods
• CPC Class Codes: G11C 11/18 using Hall-effect devices
• CPC Class Codes: H10B 61/00 Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: H10N 50/80 Constructional details
• CPC Class Codes: H10N 50/85 Magnetic active materials

Abstract

Provided is a magnetic memory device for applying an in-plane current to a conductive wire adjacent to a free magnetic layer having a perpendicular magnetic anisotropy to induce a flux reversal of the free magnetic layer and simultaneously applying a voltage to each magnetic tunnel junction cell selectively to reverse magnetization of the free magnetic layer selectively at each specific voltage. The magnetic memory device may implement high density integration by reducing a volume since a spin-hall spin-torque causing a flux reversal is generated at an interface of the conductive wire and the free magnetic layer, ensure thermal stability by enhancing perpendicular magnetic anisotropy of the magnetic layer, and reduce a critical current density by increasing an amount of spin current. In addition, by increasing tunnel magnetic resistance with a thick insulating body, the magnetic memory device may increase a reading rate without badly affecting the critical current density.

Claims

1. A magnetic memory device, comprising:

a plurality of magnetic memory cells, each including a fixed magnetic layer, an insulating layer and a free magnetic layer;

wherein the magnetic memory device comprises a conductive wire provided adjacent to the free magnetic layer to apply an in-plane current to the magnetic memory cell;

a magnetic field provided to the magnetic memory cells; and

an element configured to independently supplying a voltage to each of the magnetic memory cells,

wherein the fixed magnetic layer is a film having a fixed magnetization orientation and made of material magnetized in a direction perpendicular to a film surface,

wherein the free magnetic layer is a film having a variable magnetization orientation and made of material magnetized in a direction perpendicular to a film surface, and

wherein a magnetization orientation of each magnetic memory cell is selectively varied according to the applied in-plane current, the magnetic field provided to the magnetic memory cells, and the voltage supplied to each of the magnetic memory cells.

2. The magnetic memory device according to claim 1,

wherein the fixed magnetic layer is made of material selected from the group consisting of Fe, Co, Ni, B, Si, Zr, Pt, Tb, Pd, Cu, W, Ta and mixtures thereof.

3. The magnetic memory device according to claim 2,

wherein the fixed magnetic layer has a multi-layered film structure of a multi-layered film ((X/Y)_n, n≧

1) formed by laminating an n number of double layers, each having an X-layer and a Y-layer, and

wherein the X-layer and the Y-layer are independently made of material selected from the group consisting of Fe, Co, Ni, B, Si, Zr, Pt, Tb, Pd, Cu, W, Ta and mixtures thereof.

4. The magnetic memory device according to claim 1,

wherein the fixed magnetic layer has a diamagnetic body structure including a first magnetic layer, a non-magnetic layer and a second magnetic layer,

wherein the first magnetic layer and the second magnetic layer are independently made of material selected from the group consisting of Fe, Co, Ni, B, Si, Zr, Pt, Tb, Pd, Cu, W, Ta and mixtures thereof, and

wherein the non-magnetic layer is made of material selected from the group consisting of Ru, Cu and mixtures thereof.

5. The magnetic memory device according to claim 4,

wherein at least one of the first magnetic layer and the second magnetic layer has a multi-layered film structure of a multi-layered film ((X/Y)_n, n≧

1) formed by laminating an n number of double layers, each having an X-layer and a Y-layer, and

wherein the X-layer and the Y-layer are independently made of material selected from the group consisting of Fe, Co, Ni, B, Si, Zr, Pt, Tb, Pd, Cu, W, Ta and mixtures thereof.

6. The magnetic memory device according to claim 1,

wherein the fixed magnetic layer has an exchange-biased diamagnetic body structure including an anti-ferromagnetic layer;

a first magnetic layer;

a non-magnetic layer; and

a second magnetic layer,

wherein the anti-ferromagnetic layer is made of material selected from the group consisting of Ir, Pt, Mn and mixtures thereof,

wherein the first magnetic layer and the second magnetic layer are independently made of material selected from the group consisting of Fe, Co, Ni, B, Si, Zr, Pt, Tb, Pd, Cu, W, Ta and mixtures thereof, and

wherein the non-magnetic layer is made of material selected from the group consisting of Ru, Cu and mixtures thereof.

7. The magnetic memory device according to claim 6,

wherein at least one of the first magnetic layer and the second magnetic layer has a multi-layered film structure of a multi-layered film ((X/Y)_n, n≧

1) formed by laminating an n number of double layers, each having an X-layer and a Y-layer, and

wherein the X-layer and the Y-layer are independently made of material selected from the group consisting of Fe, Co, Ni, B, Si, Zr, Pt, Tb, Pd, Cu, W, Ta and mixtures thereof.

8. The magnetic memory device according to claim 1,

wherein the free magnetic layer is made of material selected from the group consisting of Fe, Co, Ni, B, Si, Zr, Pt, Tb, Pd, Cu, W, Ta and mixtures thereof.

9. The magnetic memory device according to claim 8,

wherein the free magnetic layer has a multi-layered film structure of a multi-layered film ((X/Y)_n, n≧

1) formed by laminating an n number of double layers, each having an X-layer and a Y-layer, and

wherein the X-layer and the Y-layer are independently made of material selected from the group consisting of Fe, Co, Ni, B, Si, Zr, Pt, Tb, Pd, Cu, W, Ta and mixtures thereof.

10. The magnetic memory device according to claim 1,

wherein the insulating layer is made of material selected from the group consisting of AlO_x, MgO, TaO_x, ZrO_x and mixtures thereof.

11. The magnetic memory device according to claim 1,

wherein the conductive wire configured to applying the in-plane current is made of material selected from the group consisting of Cu, Ta, Pt, W, Gd, Bi, Ir and mixtures thereof.

12. The magnetic memory device according to claim 1, further comprising:

a conductive wire adjacent to an outer side of the magnetic memory cell,

wherein an Oersted magnetic field formed when a current is applied to the conductive wire is used as a magnetic field provided to the magnetic memory cell.

13. The magnetic memory device according to claim 1,

wherein the magnetic memory cell further includes a magnetic layer having horizontal magnetic anisotropy at an outside of a laminated structure of the fixed magnetic layer, the insulating layer and the free magnetic layer, and

wherein a leaked magnetic field generated from the magnetic layer having horizontal magnetic anisotropy is used as a magnetic field provided to the magnetic memory cell.

14. The magnetic memory device according to claim 13,

wherein the magnetic layer having horizontal magnetic anisotropy is made of material selected from the group consisting of Fe, Co, Ni B, Si Zr and mixtures thereof.

15. The magnetic memory device according to claim 13, further comprising:

an anti-ferromagnetic layer adjacent to the magnetic layer having horizontal magnetic anisotropy,

wherein the magnetic layer having horizontal magnetic anisotropy has fixed magnetization due to the anti-ferromagnetic layer.

16. The magnetic memory device according to claim 15,

wherein the anti-ferromagnetic layer adjacent to the magnetic layer having horizontal magnetic anisotropy is made of material selected from the group consisting of IrMn, FeMn, PtMn and mixtures thereof.