MR (magnetoresistance) device and magnetic recording device

• US 20040207961A1
• Filed: 11/05/2003
• Published: 10/21/2004
• Est. Priority Date: 11/08/2002
• Status: Abandoned Application

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Hashizume, Tomihiro, Ito, Kenchi, Ichimura, Masahiko, Onogi, Toshiyuki, Matsuoka, Hideyuki
• Application Number:
  US10/700,519
• Publication Number:
  US 20040207961A1
• Time in Patent Office: Days
• 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: 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: H10B 61/22 of the field-effect transistor [FET] type
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: H10N 50/85 Magnetic active materials

Abstract

Disclosed is a magnetoresistance device which uses a ferromagnetic tunnel junction formed by inserting an insulating layer between two ferromagnetic layers and whose application to a magnetic head and a magnetoresistance memory is promising. The magnetoresistance device has a multilayer structure which has a ferromagnetic tunnel junction formed by lamination of a first ferromagnetic layer, an insulating layer and a second ferromagnetic layer, and in which at least one of the first and second ferromagnetic layers is a half-metallic ferromagnet formed of a material having such an electronic structure that one spin having a metallic band near Fermi energy has a gap at a level of higher energy than the Fermi energy and the other spin has a metallic band at the same level.

Claims

1. A magnetoresistance device with a multilayer structure which has a ferromagnetic tunnel junction formed by lamination of a first ferromagnetic layer, an insulating layer and a second ferromagnetic layer, and in which at least one of said first and second ferromagnetic layers is a half-metallic ferromagnet formed of a material having such an electronic structure that one spin having a metallic band near Fermi energy has a gap at a level of higher energy than said Fermi energy and the other spin has a metallic band at the same level.

9. The magnetoresistance device according to claim 1, wherein said magnetoresistance device has a negative resistance when magnetizations of said first and second ferromagnetic layers are parallel to each other.

10. The magnetoresistance device according to claim 1, wherein said magnetoresistance device has a negative resistance when magnetizations of said first and second ferromagnetic layers are antiparallel to each other.

11. The magnetoresistance device according to claim 1, wherein said first or second ferromagnetic layer is formed of zinc-blende type MnC.

12. The magnetoresistance device according to claim 1, wherein said first or second ferromagnetic layer has a zinc-blende type crystal structure and is formed of an Mn compound.

13. The magnetoresistance device according to claim 1, wherein said first or second ferromagnetic layer has a zinc-blende type crystal structure and has a lattice constant in a range of 4.0 to 4.5 Angstroms.

2. A magnetoresistance device with a multilayer structure which has a ferromagnetic tunnel junction formed by lamination of an antiferromagnetic layer, a first ferromagnetic layer, an insulating layer and a second ferromagnetic layer, and in which at least one of said first and second ferromagnetic layers is a half-metallic ferromagnet formed of a material having such an electronic structure that one spin having a metallic band near Fermi energy has a gap at a level of higher energy than said Fermi energy and the other spin has a metallic band at the same level.

3. A magnetoresistance device with a multilayer structure which has a ferromagnetic tunnel junction formed by lamination of a ferromagnetic layer, an insulating layer and a semiconductor layer, and in which said ferromagnetic layer is a half-metallic ferromagnet formed of a material having such an electronic structure that one spin having a metallic band near Fermi energy has a gap at a level of higher energy than said Fermi energy and the other spin has a metallic band at the same level.

4. A magnetic head comprising a magnetoresistance device with a multilayer structure which has a ferromagnetic tunnel junction formed by lamination of a first ferromagnetic layer, an insulating layer and a second ferromagnetic layer, and in which at least one of said first and second ferromagnetic layers is a half-metallic ferromagnet formed of a material having such an electronic structure that one spin having a metallic band near Fermi energy has a gap at a level of higher energy than said Fermi energy and the other spin has a metallic band at the same level.

5. A magnetic sensor comprising a magnetoresistance device with a multilayer structure which has a ferromagnetic tunnel junction formed by lamination of a first ferromagnetic layer, an insulating layer and a second ferromagnetic layer, and in which at least one of said first and second ferromagnetic layers is a half-metallic ferromagnet formed of a material having such an electronic structure that one spin having a metallic band near Fermi energy has a gap at a level of higher energy than said Fermi energy and the other spin has a metallic band at the same level.

6. A magnetic head comprising a magnetoresistance device with a multilayer structure which has a ferromagnetic tunnel junction formed by lamination of an antiferromagnetic layer, a first ferromagnetic layer, an insulating layer and a second ferromagnetic layer, and in which at least one of said first and second ferromagnetic layers is a half-metallic ferromagnet formed of a material having such an electronic structure that one spin having a metallic band near Fermi energy has a gap at a level of higher energy than said Fermi energy and the other spin has a metallic band at the same level.

7. A magnetic sensor comprising a magnetoresistance device with a multilayer structure which has a ferromagnetic tunnel junction formed by lamination of an antiferromagnetic layer, a first ferromagnetic layer, an insulating layer and a second ferromagnetic layer and in which at least one of said first and second ferromagnetic layers is a half-metallic ferromagnet formed of a material having such an electronic structure that one spin having a metallic band near Fermi energy has a gap at a level of higher energy than said Fermi energy and the other spin has a metallic band at the same level.

8. A solid state memory comprising a magnetoresistance device with a multilayer structure which has a ferromagnetic tunnel junction formed by lamination of a first ferromagnetic layer an insulating layer and a second ferromagnetic layer and in which at least one of said first and second ferromagnetic layers is a half-metallic ferromagnet formed of a material having such an electronic structure that one spin having a metallic band near Fermi energy has a gap at a level of higher energy than said Fermi energy and the other spin has a metallic band at the same level.

14. A magnetic head which comprises a magnetoresistance device with a multilayer structure which has a ferromagnetic tunnel junction formed by lamination of a first ferromagnetic layer, an insulating layer and a second ferromagnetic layer, and in which at least one of said first and second ferromagnetic layers is a half-metallic ferromagnet formed of a material having such an electronic structure that one spin having a metallic band near Fermi energy has a gap at a level of higher energy than said Fermi energy and the other spin has a metallic band at the same level wherein said magnetoresistance device has a negative resistance when magnetizations of said first and second ferromagnetic layers are antiparallel to each other and operates under a finite bias indicating a negative resistance area.