Magnetoresistive thin-film magnetic element and method for making the same

• US 6,656,604 B2
• Filed: 04/04/2001
• Issued: 12/02/2003
• Est. Priority Date: 04/06/2000
• Status: Expired due to Fees

• Current Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Hasewaga, Naoya
• Primary Examiner(s): KILIMAN, LESZEK B
• Application Number:
  US09/826,164
• Publication Number:
  US 20010038927A1
• Time in Patent Office: 972 Days
• Field of Search: 428/611, 428/622, 428/627, 428/629, 428/632, 428/639, 428/641, 428/660, 428/667, 428/670, 428/678, 428/692, 428/928, 428/900, 428/694.R, 428/668, 428/671, 428/615, 428/652, 360/113, 324/252, 338/32.R
• US Class Current: 428/611
• 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: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: G11B 2005/3996 large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices
• 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 5/3967 Composite structural arrangements of transducers, e.g. inductive write and magnetoresistive read G11B5/3906 takes precedence
• 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: H01F 41/308 lift-off processes, e.g. ion milling, for trimming or patterning
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: H10N 50/10 Magnetoresistive devices
• CPC Class Codes: Y10S 428/90 Magnetic feature
• CPC Class Codes: Y10S 428/928 Magnetic property
• CPC Class Codes: Y10T 428/11 Magnetic recording head
• CPC Class Codes: Y10T 428/1107 Magnetoresistive
• CPC Class Codes: Y10T 428/1121 Multilayer
• CPC Class Codes: Y10T 428/12465 having magnetic properties, or preformed fiber orientation coordinate with shape
• CPC Class Codes: Y10T 428/12542 More than one such component
• CPC Class Codes: Y10T 428/12576 Boride, carbide or nitride component
• CPC Class Codes: Y10T 428/1259 Oxide
• CPC Class Codes: Y10T 428/12611 : Oxide-containing component
• CPC Class Codes: Y10T 428/1266 : O, S, or organic compound in metal component
• CPC Class Codes: Y10T 428/12674 : Ge- or Si-base component
• CPC Class Codes: Y10T 428/12854 : Next to Co-, Fe-, or Ni-base component
• CPC Class Codes: Y10T 428/12861 : Group VIII or IB metal-base component
• CPC Class Codes: Y10T 428/12875 : Platinum group metal-base component
• CPC Class Codes: Y10T 428/12931 : Co-, Fe-, or Ni-base components, alternative to each other

Abstract

A magnetoresistive thin-film magnetic element including a composite comprising an antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic conductive layer, a free magnetic layer; hard bias layers for orienting the magnetic vectors of the free magnetic layer in a direction substantially orthogonal to the magnetization vector of the pinned magnetic layer; and a conductive layer for supplying a sense current is provided. The hard bias layers are provided at the two sides of the free magnetic layer. The hard bias layers and the free magnetic layers are in contact with each other at least partly. Bias underlayers are provided at the bottom of the hard bias layers.

Claims

1. A magnetoresistive thin-film magnetic element comprising:

a composite comprising an antiferromagnetic layer, a pinned magnetic layer on the antiferromagnetic layer and having a first magnetization vector pinned by an exchange anisotropic magnetic field with the antiferromagnetic layer, a nonmagnetic conductive layer on the pinned magnetic layer and a free magnetic layer formed on the nonmagnetic conductive layer and having a second magnetization vector;

hard bias layers formed on two sides of the free magnetic layer so that the side face of each hard bias layer is in direct contact with the corresponding side face of the free magnetic layer, wherein the hard bias layers orient the second magnetization vector of the free magnetic layer in a direction substantially orthogonal to the first magnetization vector of the pinned magnetic layer;

a conductive layer to supply a sense current to the free magnetic layer, the nonmagnetic conductive layer, and the pinned magnetic layer; and

bias underlayers each provided under each of the hard bias layers, wherein the bias underlayers extend at least below the hard bias layers toward the top face of the pinned magnetic layer, wherein the bias underlayers comprise a nonmagnetic metal having a body-centered cubic structure.

2. A magnetoresistive thin-film magnetic element according to claim 1, wherein the magnetoresistive thin-film magnetic element is of a dual type in which the nonmagnetic conductive layer, the pinned magnetic layer, and the antiferromagnetic layer are provided on each of opposite sides in the thickness direction of the free magnetic layer.

3. A magnetoresistive thin-film magnetic element according to claim 1, the composite further comprising at least one nonmagnetic interlayer which separates at least one of the pinned magnetic layer and the free magnetic layer into two sublayers, wherein the two sublayers are in a ferri-magnetic state in which magnetization vectors of the two sublayers are antiparallel to each other.

4. A magnetoresistive thin-film magnetic element according to claim 2, the composite further comprising at least one nonmagnetic interlayer which separates at least one of the pinned magnetic layer and the free magnetic layer into two sublayers, wherein the two sublayers are in a ferri-magnetic state in which magnetization vectors of the two sublayers are antiparallel to each other.

5. A magnetoresistive thin-film magnetic element according to claim 1, wherein the thickness of the extension of each of the bias underlayers is less than or equal to about 1 nm.

6. A magnetoresistive thin-film magnetic element according to claim 5, wherein the thickness of the extension of each of the bias underlayers is less than or equal to about 1 nm.

7. A magnetoresistive thin-film magnetic element according to claim 1, wherein the bias underlayers comprise chromium.

8. A magnetoresistive thin-film magnetic element according to claim 1, wherein the hard bias layers form slope angles along two side portions of the composite, wherein the slope angles are greater than or equal to about 30 degrees.

9. A magnetoresistive thin-film magnetic element according to claim 2, wherein the hard bias layers form slope angles along two side portions of the composite, wherein the slope angles are greater than or equal to about 30 degrees.

10. A magnetoresistive thin-film magnetic element comprising:

a composite comprising an antiferromagnetic layer, a pinned magnetic layer on the antiferromagnetic layer and having a first magnetization vector pinned by an exchange anisotropic magnetic field with the antiferromagnetic layer, a nonmagnetic conductive layer on the pinned magnetic layer, and a free magnetic layer formed on the nonmagnetic conductive layer and having a second magnetization vector;

hard bias layers formed at two sides of the composite, wherein the hard bias layers orient the second magnetization vector of the free magnetic layer in a direction substantially orthogonal to the first magnetization vector of the pinned magnetic layer, wherein the side face of each hard bias layer is in direct contact with the corresponding side face of the free magnetic layer via a pinhole provided in the corresponding underlayer;

a conductive layer to supply a sense current to the free magnetic layer, the nonmagnetic conductive layer, and the pinned magnetic layer; and

bias underlayers each provided under each of the hard bias layers, wherein the bias underlayers extend at the interfaces between the free magnetic layer and the hard bias layers, wherein the portion controls the crystal orientation of the hard bias layers, wherein the bias underlayers comprise a nonmagnetic metal having a body-centered cubic structure,

wherein the thickness of each of the hard bias underlayers is smaller at the interface between the free magnetic layer and each of the hard bias layers than under the hard bias layers.

11. A magnetoresistive thin-film magnetic element according to claim 10, wherein the magnetoresistive thin-film magnetic element is of a dual type in which the nonmagnetic conductive layer, the pinned magnetic layer, and the antiferromagnetic layer are provided on each of opposite sides in the thickness direction of the free magnetic layer.

12. A magnetoresistive thin-film magnetic element according to claim 10, the composite further comprising at least one nonmagnetic interlayer which separates at least one of the pinned magnetic layer and the free magnetic layer into two sublayers, wherein the two sublayers are in a ferri-magnetic state in which magnetization vectors of the two sublayers are antiparallel to each other.

13. A magnetoresistive thin-film magnetic element according to claim 11, the composite further comprising at least one nonmagnetic interlayer which separates at least one of the pinned magnetic layer and the free magnetic layer into two sublayers, wherein the two sublayers are in a ferri-magnetic state in which magnetization vectors of the two sublayers are antiparallel to each other.

14. A magnetoresistive thin-film magnetic element according to claim 10, wherein the thickness of the portion of each of the bias underlayers extending to the interface between the free magnetic layer and each of the hard bias layers is less than or equal to about 1 nm.

15. A magnetoresistive thin-film magnetic element according to claim 11, wherein the thickness of each of the bias underlayers is less than or equal to about 1 nm at the interface between the free magnetic layer and each of the hard bias layers.

16. A magnetoresistive thin-film magnetic element according to claim 10, wherein the bias underlayers comprise chromium.

17. A magnetoresistive thin-film magnetic element according to claim 10, wherein the hard bias layers form slope angles along two side portions of the composite, wherein the slope angles are greater than or equal to about 30 degrees.

18. A magnetoresistive thin-film magnetic element according to claim 11, wherein the hard bias layers form slope angles along two side portions of the composite, wherein the slope angles are greater than or equal to 30 degrees.