Magnetic memory device

Patent metadata

Field	Value
Publication number	US-2020302988-A1
Application number	US-201916568102-A
Country	US
Kind code	A1
Filing date	Sep 11, 2019
Priority date	Mar 20, 2019
Publication date	Sep 24, 2020
Grant date	—

Abstract

According to one embodiment, a magnetic memory device includes a magnetoresistive element including a first magnetic layer having a variable magnetization direction, a second magnetic layer having a fixed magnetization direction, and a nonmagnetic layer provided between the first magnetic layer and the second magnetic layer. The first magnetic layer contains nickel (Ni), cobalt (Co), manganese (Mn) and gallium (Ga) and has a spin polarization less than 0.71.

First claim

What is claimed is:

1 . A magnetic memory device comprising:
a magnetoresistive element comprising:
a first magnetic layer having a variable magnetization direction;
a second magnetic layer having a fixed magnetization direction; and
a nonmagnetic layer provided between the first magnetic layer and the second magnetic layer,
the first magnetic layer containing nickel (Ni), cobalt (Co), manganese (Mn) and gallium (Ga) and having a spin polarization less than 0.71.

2 . The device of claim 1 , wherein
the first magnetic layer has a spin polarization higher than 0.45.

3 . The device of claim 1 , wherein
the magnetoresistive element is a spin transfer torque (STT) magnetoresistive element.

4 . The device of claim 1 , wherein
the magnetoresistive element has perpendicular magnetization.

5 . A magnetic memory device comprising:
a magnetoresistive element comprising:
a first magnetic layer having a variable magnetization direction;
a second magnetic layer having a fixed magnetization direction; and
a nonmagnetic layer provided between the first magnetic layer and the second magnetic layer,
the first magnetic layer being formed of a Heusler alloy and having a spin polarization less than 0.71.

6 . The device of claim 5 , wherein
the first magnetic layer has a spin polarization higher than 0.45.

7 . The device of claim 5 , wherein
the first magnetic layer contains at least one of cobalt (Co) and iron (Fe), and at least one element selected from manganese (Mn), silicon (Si), germanium (Ge), aluminum (Al), gallium (Ga), tin (Sn), titanium (Ti), and vanadium (V).

8 . The device of claim 5 , wherein
the magnetoresistive element is a spin transfer torque (STT) magnetoresistive element.

9 . The device of claim 5 , wherein
the magnetoresistive element has perpendicular magnetization.

10 . A magnetic memory device comprising:
a magnetoresistive element comprising:
a first magnetic layer having a variable magnetization direction;
a second magnetic layer having a fixed magnetization direction; and
a nonmagnetic layer provided between the first magnetic layer and the second magnetic layer,
the first magnetic layer containing nickel (Ni), cobalt (Co), manganese (Mn) and gallium (Ga), when a ratio of a nickel (Ni) composition ratio to a cobalt (Co) composition ratio is set to (1−x)/x, a value of x being less than 0.45 or higher than 0.95.

11 . The device of claim 10 , wherein
the value of x is higher than 0.42 and less than 0.45, or higher than 0.95 and less than 1.00.

12 . The device of claim 10 , wherein
the magnetoresistive element is a spin transfer torque (STT) magnetoresistive element.

13 . The device of claim 10 , wherein
the magnetoresistive element has perpendicular magnetization.

Assignees

• Toshiba Memory Corp

Inventors

• Kishi Tatsuya

Classifications

• H10N50/85

  Materials of the active region · CPC title

• H10N50/10 Primary

  Magnetoresistive devices · CPC title

• H01F10/329

  Spin-exchange coupled multilayers wherein the magnetisation of the free layer is switched by a spin-polarised current, e.g. spin torque effect · CPC title

• H01F10/324

  Exchange coupling of magnetic film pairs via a very thin non-magnetic spacer, e.g. by exchange with conduction electrons of the spacer · CPC title

• G11C11/161 Primary

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