Magnetoresistive element having exchange-coupled film including PtCr/XMn antiferromagnetic bilayer

Patent metadata

Field	Value
Publication number	US-10650849-B2
Application number	US-201916271933-A
Country	US
Kind code	B2
Filing date	Feb 11, 2019
Priority date	Aug 10, 2016
Publication date	May 12, 2020
Grant date	May 12, 2020

Abstract

An exchange-coupled film according to the present invention includes an antiferromagnetic layer, pinned magnetic layer, and free magnetic layer which are stacked. The antiferromagnetic layer is composed of a Pt—Cr sublayer and an X—Mn sublayer (where X is Pt or Ir). The X—Mn sublayer is in contact with the pinned magnetic layer. The Pt—Cr sublayer has a composition represented by the formula PtαCr100 at %-α (α is 44 at % to 58 at %) when the X—Mn sublayer is placed on the Pt—Cr sublayer or has a composition represented by the formula PtαCr100 at %-α (α is 44 at % to 57 at %) when the X—Mn sublayer is placed on the pinned magnetic layer.

First claim

What is claimed is:

1. An exchange-coupled film comprising
an antiferromagnetic layer composed of a Pt—Cr sublayer and an X—Mn sublayer (where X is Pt or Ir); and
a pinned magnetic layer, the antiferromagnetic layer and the pinned magnetic layer being stacked,
wherein the X—Mn sublayer is in contact with the pinned magnetic layer, and the Pt—Cr sublayer has a composition represented by the formula Pt α Cr 100 at %-α (α is 44 at % to 58 at %) when the X—Mn sublayer is placed on the Pt—Cr sublayer or has a composition represented by the formula Pt α Cr 100 at %-α (α is 44 at % to 57 at %) when the X—Mn sublayer is placed on the pinned magnetic layer.

2. The exchange-coupled film according to claim 1 , wherein the pinned magnetic layer is a self-pinned layer including a first magnetic sublayer, intermediate sublayer, and second magnetic sublayer which are stacked.

3. The exchange-coupled film according to claim 1 , wherein the thickness of the Pt—Cr sublayer is greater than the thickness of the X—Mn sublayer.

4. The exchange-coupled film according to claim 3 , wherein the ratio of the thickness of the Pt—Cr sublayer to the thickness of the X—Mn sublayer is 5:1 to 100:1.

5. The exchange-coupled film according to claim 1 , wherein the Pt—Cr sublayer has a composition represented by the formula Pt α Cr 100 at %-α (α is 45 at % to 57 at %) when the X—Mn sublayer is placed on the Pt—Cr sublayer or has a composition represented by the formula Pt α Cr 100 at %-α (α is 45 at % to 56 at %) when the X—Mn sublayer is placed on the pinned magnetic layer.

6. The exchange-coupled film according to claim 1 , wherein the Pt—Cr sublayer has a composition represented by the formula Pt α Cr 100 at %-α (α is 48 at % to 55 at %) when the X—Mn sublayer is placed on the Pt—Cr sublayer or has a composition represented by the formula Pt α Cr 100 at %-α (α is 47 at % to 55 at %) when the X—Mn sublayer is placed on the pinned magnetic layer.

7. The exchange-coupled film according to claim 1 , further comprising a base layer next to the antiferromagnetic layer, wherein the base layer is made of Ni—Fe—Cr.

8. A magnetoresistive element comprising the exchange-coupled film according to claim 1 and a free magnetic layer, the exchange-coupled film and the free magnetic layer being stacked.

9. A magnetic sensing device comprising the magnetoresistive element according to claim 8 .

10. The magnetic sensing device according to claim 9 , further comprising a plurality of magnetoresistive elements, placed on a single substrate, identical to the magnetoresistive element according to claim 8 , wherein a plurality of the magnetoresistive elements include those having different pinned magnetization directions.

11. A method for manufacturing an exchange-coupled film including an antiferromagnetic layer and pinned magnetic layer which are stacked, the antiferromagnetic layer being composed of a Pt—Cr sublayer and an X—Mn sublayer (where X is Pt or Ir), the X—Mn sublayer being in contact with the pinned magnetic layer, the method comprising:
forming the Pt—Cr sublayer such that the Pt—Cr sublayer has a composition represented by the formula Pt α Cr 100 at %-α (α is 44 at % to 58 at %) in the case where the X—Mn sublayer is stacked on the Pt—Cr sublayer or
forming the Pt—Cr sublayer such that the Pt—Cr sublayer has a composition represented by the formula Pt α Cr 100 at %-α (α is 44 at % to 57 at %) in the case where the X—Mn sublayer is stacked on the pinned magnetic layer.

Assignees

• Alps Alpine Co Ltd

Inventors

• Saito Masamichi
• Koike Fumihito
• Endo Hiroaki

Classifications

• G01R33/007

  Environmental aspects, e.g. temperature variations, radiation, stray fields (G01R33/025 takes precedence) · CPC title

• G11B5/3945

  Heads comprising more than one sensitive element · CPC title

• H01F10/3272

  by use of anti-parallel coupled [APC] ferromagnetic layers, e.g. artificial ferrimagnets [AFI], artificial [AAF] or synthetic [SAF] anti-ferromagnets · CPC title

• H01F10/12

  being metals or alloys (intermetallic compounds H01F10/18) · CPC title

• G11B2005/3996

  large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices · CPC title