Magnetoresistive effect element, magnetic head, and magnetic disk apparatus

• US 8,917,485 B2
• Filed: 10/13/2006
• Issued: 12/23/2014
• Est. Priority Date: 03/27/2006
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Fukuzawa, Hideaki, Kurosaki, Yoshinari, Yuasa, Hiromi, Fuji, Yoshihiko, Iwasaki, Hitoshi
• Primary Examiner(s): Young, Wayne
• Assistant Examiner(s): Garcia, Carlos E
• Application Number:
  US11/546,975
• Publication Number:
  US 20070223150A1
• Time in Patent Office: 2,993 Days
• Field of Search: 360/324.11, 360/324.1
• US Class Current: 360/324.1
• 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: G11B 5/3903 using magnetic thin film layers or their effects, the films being part of integrated structures
• CPC Class Codes: G11B 5/398 Specially shaped layers
• CPC Class Codes: G11B 5/455 Arrangements for functional testing of heads; Measuring arrangements for heads
• CPC Class Codes: G11C 11/16 using elements in which the storage effect is based on magnetic spin effect
• CPC Class Codes: H01F 10/3254 the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]
• CPC Class Codes: H01F 10/3259 Spin-exchange-coupled multilayers comprising at least a nanooxide layer [NOL], e.g. with a NOL spacer
• CPC Class Codes: H01F 10/3272 by use of anti-parallel coupled [APC] ferromagnetic layers, e.g. artificial ferrimagnets [AFI], artificial [AAF] or synthetic [SAF] anti-ferromagnets
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

A magnetoresistive effect element includes a magnetization fixed layer including a first crystal grain, having a magnetization direction which is fixed substantially in one direction, a spacer layer arranged on the magnetization fixed layer and having an insulating layer and a metal conductor penetrating the insulating layer, and a magnetization free layer including a second crystal grain, arranged on the spacer layer to oppose the metal conductor and having a magnetization direction which changes corresponding to an external magnetic field.

Claims

1. A magnetoresistive effect element, comprising:

a magnetization fixed layer including a plurality of first crystal grains, having a magnetization direction which is fixed substantially in one direction;

a magnetization free layer including a plurality of second crystal grains, having a magnetization direction which is changeable; and

a spacer layer, between the magnetization fixed layer the magnetization free layer, including an insulating layer and a plurality of metal conductors penetrating the insulating layer,

grain diameters of the second crystal grains being smaller than grain diameters of the first crystal grains,

the metal conductors having diameters smaller than the grain diameters of both the first and second crystal grains, and

each metal conductor being arranged in correspondence with a center portion of a corresponding one of the first crystal grains and a center portion of a corresponding one of the second crystal grains.

2. The magnetoresistive effect element according to claim 1, wherein grain diameters of the second crystal grains are 3 nanometers or larger and 10 nanometers or smaller.

3. The magnetoresistive effect element according to claim 1, further comprising

a first metal layer arranged between the magnetization free layer and the spacer layer, the first metal layer including a first component in common with the metal conductor.

4. The magnetoresistive effect element according to claim 3, wherein the first component includes at least one of copper, gold, and silver.

5. The magnetoresistive effect element according to claim 4, wherein a film thickness of the first metal layer is 0.2 nanometer or larger and 1.5 nanometer or smaller.

6. The magnetoresistive effect element according to claim 3, further comprising

a second metal layer arranged between the magnetization fixed layer and the spacer layer, the second metal layer including a second component in common with the metal conductor.

7. The magnetoresistive effect element according to claim 6, wherein the second component includes at least one of copper, gold, and silver.

8. The magnetoresistive effect element according to claim 6, wherein a film thickness of the second metal layer is 0.1 nanometer or larger and 1.0 nanometer or smaller.

9. The magnetoresistive effect element according to claim 6, wherein the first metal layer is thicker than the second metal layer.

10. The magnetoresistive effect element according to claim 1, wherein the magnetization fixed layer includes an iron-cobalt layer having a body-centered cubic structure or a cobalt-iron layer having a face-centered cubic structure, and the magnetization free layer includes a cobalt-iron alloy layer.

11. The magnetoresistive effect element according to claim 1, wherein the metal conductor has a diameter of 2 nanometers or larger and 6 nanometers or smaller.

12. The magnetoresistive effect element according to claim 1, wherein the metal conductor has a crystal structure, and the insulating layer has an amorphous structure.

13. The magnetoresistive effect element according to claim 1, wherein the insulating layer includes an oxide, a nitride, or an oxynitride which includes at least one kind of element selected from the group consisting of aluminum, silicon, hafnium, titanium, tantalum, molybdenum, tungsten, niobium, magnesium, chromium, and zirconium.

14. The magnetoresistive effect element according to claim 1, further comprising

a pair of electrodes which passes a current from the magnetization fixed layer to the magnetization free layer.

15. A magnetic head comprising a magnetoresistive effect element according to claim 14.

16. A magnetic disk apparatus comprising a magnetic head according to claim 15.

17. The magnetoresistive effect element according to claim 1, wherein the grain diameters of the first crystal grains are between 5 and 20 nanometers.

18. The magnetoresistive effect element according to claim 1, wherein each of the magnetization fixed layer and the magnetization free layer has a crystal structure which is at least one of face-centered cubic (111) orientation, body-centered cubic (110) orientation, hexagonal close-packed (001) orientation, and hexagonal close-packed (110) orientation, perpendicular to a face thereof, with a dispersion angle of crystal orientation being 4.0 degrees or less.

19. The magnetoresistive effect element according to claim 1, wherein

first and second ends of the longest straight line traversing each respective one of the first crystal grains are designated with coordinates 0 and 100, respectively, and the center portion of each respective first crystal grain is defined as an area between coordinates 30 and 70 of that first crystal grain, and

first and second ends of the longest straight line traversing each respective one of the second crystal grains are designated with coordinates 0 and 100, respectively, and the center portion of each respective second crystal grain is defined as an area between coordinates 30 and 70 of that second crystal grain.

20. The magnetoresistive effect element according to claim 1, wherein a range of grain diameters of the second crystal grains in the vicinity of the metal conductors is different than a range of grain diameters of the second crystal grains in other portions of the magnetization free layer.