Magnetoresistance effect element

Patent metadata

Field	Value
Publication number	US-11763841-B2
Application number	US-202117412394-A
Country	US
Kind code	B2
Filing date	Aug 26, 2021
Priority date	Mar 31, 2015
Publication date	Sep 19, 2023
Grant date	Sep 19, 2023

Abstract

A magnetoresistance effect element has a first ferromagnetic metal layer, a second ferromagnetic metal layer, and a tunnel barrier layer that is sandwiched between the first and second ferromagnetic metal layers, the tunnel barrier layer is expressed by a chemical formula of AB2Ox, and has a spinel structure in which cations are arranged in a disordered manner, A represents a divalent cation that is either Mg or Zn, and B represents a trivalent cation that includes a plurality of elements selected from the group consisting of Al, Ga, and In.

First claim

The invention claimed is:

1. A magnetoresistance effect element comprising:
a first ferromagnetic metal layer;
a second ferromagnetic metal layer; and
a tunnel barrier layer that is sandwiched between the first and second ferromagnetic metal layers,
wherein the tunnel barrier layer has a spinel structure,
the tunnel barrier layer comprises a lattice-matched portion and a lattice-mismatched portion, the lattice-matched portion lattice-matching with both of the first and second ferromagnetic metal layers, the lattice-mismatched portion not lattice-machining with at least one of the first and second ferromagnetic metal layers,
an underlayer is provided underneath the first ferromagnetic metal layer on a side opposite to the tunnel barrier layer,
the underlayer has a NaCl crystal structure oriented in a (001) orientation, and the underlayer is made of a nitride containing at least one element selected from a group consisting of Ti, Zr, Nb, V, Hf, Ta, Mo, W, B, Al and Ce, and wherein
when viewed as an inverse Fourier transform image in a stacking direction of a cross-section TEM image of the interface between the tunnel barrier layer and the first and/or the second ferromagnetic metal layer, a lattice-matched portion is made up of a plurality of sequential, continuously-connected lattice lines, and a lattice-mismatched portion is made up of a plurality of sequential, non-continuously-connected lattice lines and/or no lattice lines, and
wherein the tunnel barrier layer is expressed by a chemical formula of AB 2 O X (0<X≤4), and has a spinel structure in which cations are arranged in a disordered manner,
A represents a divalent cation that is either Mg or Zn, and
B represents a trivalent cation that includes a plurality of elements selected from a group consisting of Al, Ga, and In.

2. The magnetoresistance effect element according to claim 1 , wherein a volume ratio of the lattice-matched portion with respect to a volume of the entire tunnel barrier layer is 65% to 95%.

3. The magnetoresistance effect element according to claim 1 , wherein a difference in ionic radius between the plurality of elements of the trivalent cation is 0.2 Å or less.

4. The magnetoresistance effect element according to claim 1 , wherein the number of constituent elements in a unit cell of the divalent cation is smaller than half that of the trivalent cation.

5. The magnetoresistance effect element according to claim 1 , wherein a magnetoresistance ratio is 100% or greater under application of a bias voltage of 1 V or greater at a room temperature.

6. The magnetoresistance effect element according to claim 1 , wherein the first ferromagnetic metal layer has larger coercivity than the second ferromagnetic metal layer.

7. The magnetoresistance effect element according to claim 1 , wherein at least one of the first ferromagnetic metal layer and the second ferromagnetic metal layer has magnetic anisotropy perpendicular to a stacking direction.

8. The magnetoresistance effect element according to claim 1 , wherein at least one of the first ferromagnetic metal layer and the second ferromagnetic metal layer is Co2Mn1−aFeaAlbSi1−b (0≤a≤1, 0≤b≤1).

9. The magnetoresistance effect element according to claim 1 , wherein in the trivalent cation, a proportion of any one of Al, Ga, or In as a main component is 85% to less than 100%.

Assignees

• Tdk Corp

Inventors

• Sasaki Tomoyuki

Classifications

• H01F10/1936

  Half-metallic, e.g. epitaxial CrO2 or NiMnSb films · CPC title

• G11B5/3909 Primary

  Arrangements using a magnetic tunnel junction · CPC title

• G11C11/161

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

• H10B61/22

  of the field-effect transistor [FET] type · CPC title

• H10N50/01

  Manufacture or treatment · CPC title