Magnetic tunnel junction device with spin-filter structure

Patent metadata

Field	Value
Publication number	US-2018190899-A1
Application number	US-201715639662-A
Country	US
Kind code	A1
Filing date	Jun 30, 2017
Priority date	Jan 3, 2017
Publication date	Jul 5, 2018
Grant date	—

Abstract

A magnetic device includes a conductive layer into which current can be injected in a first direction, the conductive layer causing spin Hall effect or Rashba effect. A ferromagnetic layer is disposed in contact with the conductive layer such that the ferromagnetic layer and the conductive layer are stacked on each other, a magnetization direction of the ferromagnetic layer being switched. A spin filter structure has a fixed magnetization direction, the spin filter structure being disposed on at least one of the opposite side surfaces of the first direction of the conductive layer to inject spin-polarized current into the conductive layer.

First claim

What is claimed is:

1 . A magnetic device comprising:
a conductive layer into which current can be injected in a first direction, the conductive layer causing spin Hall effect or Rashba effect; a ferromagnetic layer disposed in contact with the conductive layer such that the ferromagnetic layer and the conductive layer are stacked on each other, a magnetization direction of the ferromagnetic layer being switched; and a spin filter structure having a fixed magnetization direction, the spin filter structure being disposed on at least one of opposite side surfaces of the first direction of the conductive layer to inject spin-polarized current into the conductive layer.

2 . The magnetic device as set forth in claim 1 , wherein spin polarization of the spin filter structure is greater than 0 and equal to or smaller than 1.

3 . The magnetic device as set forth in claim 1 , wherein the spin filter structure is a half-metallic ferromagnet.

4 . The magnetic device as set forth in claim 3 , wherein the half-metallic ferromagnet includes at least one of a Heusler alloy, magnetite (Fe 3 O 4 ), and lanthanum strontium manganite (LSMO).

5 . The magnetic device as set forth in claim 1 , wherein the spin filter structure includes a ferromagnet, and
a magnetization direction of the spin filter structure is parallel or antiparallel to a magnetization direction of the ferromagnetic layer.

6 . The magnetic device as set forth in claim 1 , wherein a magnetization direction of the spin filter structure is antiparallel at opposite sides of the conductive layer when the spin filter structure is disposed on opposite side surfaces of the conductive layer.

7 . The magnetic device as set forth in claim 1 , wherein a spin-flip diffusion length of the conductive layer is between 3 and 4 nanometers.

8 . The magnetic device as set forth in claim 1 , wherein the conductive layer and the ferromagnetic layer are aligned with each other.

9 . A magnetic tunnel junction device comprising:
a magnetic tunnel junction comprising a pinned magnetic layer, a free magnetic layer, and a tunnel barrier layer interposed between the pinned magnetic layer and the free magnetic layer; a conductive pattern to which in-plane current can flow, the conductive pattern being disposed adjacent to the free magnetic layer of the magnetic tunnel junction to cause spin Hall effect or Rashba effect to apply a spin torque to the free magnetic layer of the magnetic tunnel junction; and a spin filter structure disposed on at least one of opposite side surfaces of the conductive pattern in a direction in which in-plane current is applied, wherein the spin filter structure is configured to filter injected current to control amount and direction of a spin and to supply filtered current to the conductive pattern.

10 . The magnetic tunnel junction device as set forth in claim 9 , wherein spin polarization of the spin filter structure is greater than 0 and equal to or smaller than 1.

11 . The magnetic tunnel junction device as set forth in claim 9 , wherein the spin filter structure is a half-metallic ferromagnet.

12 . The magnetic tunnel junction device as set forth in claim 11 , wherein the half-metallic magnet includes at least one of a Heusler alloy, magnetite (Fe 3 O 4 ), and lanthanum strontium manganite (LSMO).

13 . The magnetic tunnel junction device as set forth in claim 9 , wherein the spin filter structure includes a ferromagnet, and
a magnetization direction of the spin filter structure is parallel or antiparallel to a magnetization of the free magnetic layer.

14 . The magnetic tunnel junction device as set forth in claim 9 , wherein a magnetization direction of the spin filter structure is antiparallel at opposite sides of the conductive layer when the spin filter structure is disposed on opposite side surfaces of the conductive layer.

15 . The magnetic tunnel junction device as set forth in claim 9 , wherein the conductive pattern and the free magnetic layer are aligned with each other.

16 . The magnetic tunnel junction device as set forth in claim 9 , wherein the free magnetic layer has perpendicular magnetic anisotropy (PMA).

17 . The magnetic tunnel junction device as set forth in claim 9 , wherein a spin-flip diffusion length of the conductive pattern is between 3 and 4 nanometers.

18 . The magnetic tunnel junction device as set forth in claim 9 , wherein the pinned magnetic layer has a synthetic antiferromagnetic structure including a first pinned magnetic layer, a non-magnetic layer for a pinned magnetic layer, and a second pinned magnetic layer which are sequentially stacked,
each of the first pinned magnetic layer and the second pinned magnetic layer independently includes at least one of Fe, Co, Ni, Gd, B, Si, Zr, and a combination thereof, and the non-magnetic layer for a pinned magnetic layer includes at least one of Ru, Ta, Cu, Pt, Pd, W, Cr, and a combination thereof.

19 . The magnetic tunnel junction device as set forth in claim 9 , wherein the pinned magnetic layer has an exchange-biased antiferromagnetic structure including an antiferromagnetic layer, a first pinned magnetic layer, a non-magnetic layer for a pinned magnetic layer, and a second pinned magnetic layer which are sequentially stacked,
the antiferromagnetic layer is formed of one selected from the group consisting of Pt, Ir, Fe, Mn, and a combination thereof, each of the first pinned magnetic layer and the second pinned magnetic layer independently includes at least one of Fe, Co, Ni, Gd, B, Si, Zr, and a combination thereof, and the non-magnetic layer for a pinned magnetic layer includes at least one of Ru, Ta, Cu, Pt, Pd, W, Cr, and a combination thereof.

20 . The magnetic tunnel junction device as set forth in claim 9 , wherein the tunnel barrier layer is formed of one selected from the group consisting of AlO x , MgO, TaO x , ZrO x , and a combination thereof.

21 . The magnetic tunnel junction device as set forth in claim 9 , wherein the conductive pattern provides a spin-orbit torque (SOT) resulting from a spin-orbit coupling force between the free magnetic layer and the conductive pattern, and
the conductive pattern is formed of one selected from the group consisting of Cu, Ta, Pt, W, Bi, Ir, Mn, Ti, Cr, Pd, Re, Os, Hf, Mo, Ru, and a combination thereof.

22 . The magnetic tunnel junction device as set forth in claim 9 , wherein the free magnetic layer includes at least one magnetic domain structure.

23 . The magnetic tunnel junction device as set forth in claim 9 , wherein the conductive pattern applying the in-plane current includes an antiferromagnetic layer and a ferromagnetic layer which are sequentially stacked,
the antiferromagnetic layer is disposed adjacent to the free magnetic layer, the ferromagnetic layer has an in-plane magnetization direction, the conductive pattern provides an in-plane exchange bias magnetic field to the free magnetic layer, and the free magnetic layer is switched without an external magnetic field.

24 . The magnetic tunnel junction device as set forth in claim 9 , further comprising:
a dipole field non-magnetic layer and a dipole field magnetic layer having an in-plane magnetization direction which are sequentially stacked adjacent to the pinned magnetic layer, the dipole field non-magnetic layer is disposed adjacent to the pinned magnetic layer, and the free magnetic layer is switched without an external ma

Assignees

• Univ Korea Res & Bus Found

Inventors

• Kim Young Keun
• Lee Kyung-Jin
• Go Gyungchoon

Classifications

• G11C11/18

  using Hall-effect devices · CPC title

• G11C11/161

  details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell · CPC title

• G11C11/1675

  Writing or programming circuits or methods · CPC title

• G11C11/1653

  Address circuits or decoders · CPC title

• G11C11/1657

  Word-line or row circuits · CPC title