MAGNETORESISTANCE EFFECT ELEMENT

• US 20190221735A1
• Filed: 03/26/2019
• Published: 07/18/2019
• Est. Priority Date: 03/31/2015
• Status: Active Grant

• Current Assignee: TDK Corporation
• Original Assignee: TDK Corporation
• Inventors: SASAKI, Tomoyuki, NAKADA, Katsuyuki, SHIBATA, Tatsuo
• Granted Patent: US 10,446,740 B2
• Time in Patent Office: Days
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• CPC Class Codes: G01R 33/098 comprising tunnel junctions, e.g. tunnel magnetoresistance sensors
• CPC Class Codes: G11B 5/3909 Arrangements using a magnetic tunnel junction
• 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: H01L 27/105 including field-effect components
• CPC Class Codes: H01L 29/82 controllable by variation of the magnetic field applied to the device
• 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 50/85 Magnetic active materials

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, and the tunnel barrier layer has a spinel structure represented by a composition formula of AIn₂O_x (0<x≤4), and an A-site is a non-magnetic divalent cation which is one or more selected from a group consisting of magnesium, zinc and cadmium.

Claims

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 comprising a divalent cation and a trivalent cation in a unit cell wherein a concentration of constituent elements of the divalent cation in the unit cell is more than half a concentration of constituent elements of the trivalent cation in the unit cell, and

wherein the divalent cation is a non-magnetic divalent cation which is one or more selected from a group consisting of magnesium, zinc and cadmium,

wherein the tunnel barrier layer comprises;

at least one lattice-matched portion that is lattice-matched with both of the first ferromagnetic metal layer and the second ferromagnetic metal layer; and

at least one lattice-mismatched portion that is not lattice-matched with at least one of the first ferromagnetic metal layer and the second ferromagnetic metal layer,

and wherein, when viewed 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.

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 the tunnel barrier layer has a spinel structure in which an atomic arrangement is disordered.

4. The magnetoresistance effect element according to claim 1,

wherein the first ferromagnetic metal layer has larger coercivity than that of the second ferromagnetic metal layer.

5. The magnetoresistance effect element according to claim 1,

wherein the tunnel barrier layer has a film thickness of 0.7 nm to 1.7 nm.

6. 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.

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 is Co₂Mn_1-aFe_aAl_bSi_1-b (0≤

a≤

1, 0≤

b≤

1).