Ferromagnetic tunnel magnetoresistive devices and magnetic head

• US 7,212,385 B2
• Filed: 07/14/2006
• Issued: 05/01/2007
• Est. Priority Date: 12/26/2000
• Status: Expired due to Fees

• Current Assignee: Hitachi Global Storage Technologies Japan Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi Global Storage Technologies Japan Limited (Hitachi, Ltd.)
• Inventors: Hayakawa, Jun
• Primary Examiner(s): Chen; Tianjie
• Application Number:
  US11/486,115
• Publication Number:
  US 20060256480A1
• Time in Patent Office: 291 Days
• Field of Search: 360/324.2, 360/314, 360/315, 360/316
• US Class Current: 360/324.2
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• 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 2005/0018 by current biasing control or regulation
• CPC Class Codes: G11B 5/39 using magneto-resistive devices or effects
• CPC Class Codes: G11B 5/3903 using magnetic thin film layers or their effects, the films being part of integrated structures
• CPC Class Codes: G11B 5/3909 Arrangements using a magnetic tunnel junction
• CPC Class Codes: G11B 5/3951 the active elements being arranged on several parallel planes
• CPC Class Codes: G11B 5/3967 Composite structural arrangements of transducers, e.g. inductive write and magnetoresistive read G11B5/3906 takes precedence
• CPC Class Codes: G11B 5/553 Details
• CPC Class Codes: G11B 5/59683 for magnetoresistive heads
• CPC Class Codes: H01F 10/00 Thin magnetic films, e.g. of one-domain structure magnetic record carriers G11B5/00; thin-film magnetic stores G11C
• CPC Class Codes: H01F 10/1936 Half-metallic, e.g. epitaxial CrO2 or NiMnSb films
• CPC Class Codes: H01F 10/3254 the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]
• CPC Class Codes: H01F 10/3263 the exchange coupling being symmetric, e.g. for dual spin valve, e.g. NiO/Co/Cu/Co/Cu/Co/NiO
• CPC Class Codes: H01F 10/3268 the exchange coupling being asymmetric, e.g. by use of additional pinning, by using antiferromagnetic or ferromagnetic coupling interface, i.e. so-called spin-valve [SV] structure, e.g. NiFe/Cu/NiFe/FeMn
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

The present invention provides a ferromagnetic tunnel magnetoresistive film which is associated with a high output and whose magnetoresistive ratio is less dependent on a bias voltage. In a three-terminal ferromagnetic tunnel magnetoresistive element, a decrease in an output is suppressed by a bias voltage V₁ applied to one of the tunnel junctions. By employing half-metallic ferromagnets 11 and 12 in the element, the output can be enhanced and the dependency on the applied bias voltage can be reduced.

Claims

1. A ferromagnetic tunnel magnetoresistive element, comprising:

a first antiferromagnetic layer;

a half-metallic ferromagnetic layer formed on the first antiferromagnetic layer;

a first insulating barrier layer formed on the first half-metallic ferromagnetic layer;

a first ferromagnetic metal layer formed on the first insulating barrier layer;

a second insulating barrier layer formed on the first ferromagnetic metal layer;

a second ferromagnetic metal layer formed on the second insulating barrier layer; and

a second antiferromagnetic layer formed on the second ferromagnetic metal layer,

wherein the element further comprises a first terminal for applying a first bias voltage between the half-metallic ferromagnetic layer and the second ferromagnetic metal layer, and a second terminal for applying a second bias voltage between the first ferromagnetic metal layer and the half-metallic ferromagnetic layer or the second ferromagnetic metal layer.

2. A ferromagnetic tunnel magnetoresistive element according to claim 1, wherein the first ferromagnetic metal layer is formed of a lamination of three ferromagnetic metal layers.

3. A magnetic head provided with a magnetoresistive element comprising:

a first antiferromagnetic layer;

a half-metallic ferromagnetic layer formed on the first antiferromagnetic layer;

a first insulating barrier layer formed on the first half-metallic ferromagnetic layer;

a first ferromagnetic metal layer formed on the first insulating barrier layer;

a second insulating barrier layer formed on the first ferromagnetic metal layer;

a second ferromagnetic metal layer formed on the second insulating barrier layer; and

a second antiferromagnetic layer formed on the second ferromagnetic metal layer,

wherein the element further comprises a first terminal for applying a first bias voltage between the half-metallic ferromagnetic layer and the second ferromagnetic metal layer, and a second terminal for applying a second bias voltage between the first ferromagnetic metal layer and the half-metallic ferromagnetic layer or the second ferromagnetic metal layer.

4. A magnetic head according to claim 3, wherein the first ferromagnetic metal layer is formed of a lamination of three ferromagnetic metal layers.