Spin oscillator or magnetic recorder including multiple injection layers in the magnetic recording head

• US 8,472,140 B2
• Filed: 02/24/2012
• Issued: 06/25/2013
• Est. Priority Date: 09/03/2009
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Iwasaki, Hitoshi, Takagishi, Masayuki, Funayama, Tomomi, Takashita, Masahiro, Koui, Katsuhiko, Oikawa, Soichi, Yamada, Kenichiro, Kitazaki, Mariko
• Primary Examiner(s): CASTRO, ANGEL A
• Application Number:
  US13/404,046
• Publication Number:
  US 20120154952A1
• Time in Patent Office: 487 Days
• Field of Search: 360/125.12, 360/125.3, 360/125.31, 360/324.1
• US Class Current: 360/125.3
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G11B 5/02 Recording, reproducing, or erasing methods; Read, write or erase circuits therefor
• CPC Class Codes: G11B 5/3133 including layers not usually being a part of the electromagnetic transducer structure and providing additional features, e.g. for improving heat radiation, reduction of power dissipation, adaptations for measurement or indication of gap depth or other properties of the structure G11B5/3106 takes precedence
• CPC Class Codes: G11B 5/3146 magnetic layers
• CPC Class Codes: H01F 10/3254 the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]
• CPC Class Codes: H01F 10/3286 Spin-exchange coupled multilayers having at least one layer with perpendicular magnetic anisotropy
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

A magnetic recorder includes: a magnetic recording medium; a reproducing head; a magnetic recording head including: a main magnetic pole; a first magnetic layer containing a TM alloy; a second magnetic layer containing a TM alloy or an RE-TM alloy; a third magnetic layer containing an RE-TM alloy; a first intermediate layer provided between the first magnetic layer and the second magnetic layer; and a second intermediate layer provided between the second magnetic layer and the third magnetic layer; and a signal processing portion which performs signal writing into the magnetic recording medium by using the magnetic recording head and reading from the magnetic recording medium by using the reproducing head.

Claims

1. A spin torque oscillator comprising:

a magnetic recording medium;

a reproducing head;

a magnetic recording head including;

a main magnetic pole;

a first spin injection layer containing a transition metal (TM) alloy;

a field generation layer containing a TM alloy or a rare earth transition metal (RE-TM) alloy;

a second spin injection layer containing an RE-TM alloy;

a first intermediate layer provided between the first spin injection layer and the field generation layer; and

a second intermediate layer provided between the field generation layer and the second spin injection layer.

2. The spin torque oscillator according to claim 1, wherein:

the first spin injection layer is an artificial lattice containing a TM alloy.

3. The spin torque oscillator according to claim 1, wherein:

the field generation layer is a laminated ferri-structure or an artificial lattice containing a TM alloy.

4. The spin torque oscillator according to claim 1, wherein:

the second spin injection layer is a laminated ferri-structure.

5. The spin torque oscillator according to claim 1, wherein:

the first spin injection layer, the field generation layer and the second spin injection layer have coercive force weaker than a magnetic field applied from the main magnetic pole.

6. The spin torque oscillator according to claim 1, wherein:

the RE-TM alloy in the field generation layer or the second spin injection layer is provided so that a magnetization of a rare earth element in the RE-TM alloy is larger than a magnetization of a transition metal in the RE-TM alloy.

7. A magnetic recorder comprising:

a magnetic recording medium;

a reproducing head;

a magnetic recording head including;

a main magnetic pole;

a first magnetic layer containing a transition metal (TM) alloy;

a second magnetic layer containing a TM alloy or a rare earth transition metal (RE-TM) alloy;

a third magnetic layer containing an RE-TM alloy;

a first intermediate layer provided between the first magnetic layer and the second magnetic layer; and

a second intermediate layer provided between the second magnetic layer and the third magnetic layer; and

a signal processing portion which performs signal writing into the magnetic recording medium by using the magnetic recording head and reading from the magnetic recording medium by using the reproducing head.

8. The magnetic recorder according to claim 7, wherein:

a laminate of the first magnetic layer, the second magnetic layer, the third magnetic layer, the first intermediate layer, and the second intermediate layer is laminated in a direction substantially perpendicular to a medium moving direction.

9. The magnetic recorder according to claim 7, wherein:

a laminate of the first magnetic layer, the second magnetic layer, the third magnetic layer, the first intermediate layer, and the second intermediate layer is laminated in a direction substantially parallel to a medium moving direction.

10. The magnetic recorder according to claim 7, wherein:

the magnetic recording medium is a discrete track medium having adjacent recording tracks formed through a nonmagnetic member.

11. The magnetic recorder according to claim 7, wherein:

the magnetic recording medium is a discrete bit medium having isolated recording magnetic dots arranged and formed regularly through a nonmagnetic member.