MAGNETIC RECORDING APPARATUS

• US 20160180906A1
• Filed: 10/29/2015
• Published: 06/23/2016
• Est. Priority Date: 12/22/2014
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: KUDO, Kiwamu, NAGASAWA, Tazumi, SUTO, Hirofumi, MIZUSHIMA, Koichi, SATO, Rie
• Granted Patent: US 9,704,552 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G11B 5/012 Recording on, or reproducing or erasing from, magnetic disks G11B17/00, G11B19/00 take precedence
• CPC Class Codes: G11B 5/02 Recording, reproducing, or erasing methods; Read, write or erase circuits therefor
• CPC Class Codes: G11B 5/1278 specially adapted for magnetisations perpendicular to the surface of the record carrier
• CPC Class Codes: G11B 5/2654 for recording or erasing
• CPC Class Codes: G11B 5/314 where the layers are extra layers normally not provided in the transducing structure, e.g. optical layers G11B5/3196 takes precedence
• CPC Class Codes: G11C 11/161 details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell
• CPC Class Codes: G11C 11/1673 Reading or sensing circuits or methods
• CPC Class Codes: G11C 11/1675 Writing or programming circuits or methods
• CPC Class Codes: G11C 11/5607 using magnetic storage elements

Abstract

According to one embodiment, a magnetic recording apparatus includes a spin-torque oscillator, a recording unit, and a controller. The spin-torque oscillator includes an oscillation layer. The recording unit includes at least one recording layer. Magnetization reversal in each recording layer is performed by excitation of cooperative dynamics between magnetization of the oscillation layer and magnetization of the recording layer. The controller controls precession of the magnetization of the oscillation layer, which is induced by application of an electric current to the spin-torque oscillator.

Claims

1. A magnetic recording apparatus comprising:

a spin-torque oscillator including an oscillation layer;

a recording unit including at least one recording layer, wherein magnetization reversal in each recording layer is performed by excitation of cooperative dynamics between magnetization of the oscillation layer and magnetization of the recording layer; and

a controller controlling precession of the magnetization of the oscillation layer, which is induced by application of an electric current to the spin-torque oscillator.

2. The apparatus according to claim 1, wherein the recording unit includes a plurality of recording layers having different magnetic resonance frequencies, and

the controller controls a frequency of the precession to select a recording layer of a write target from the plurality of recording layers.

3. The apparatus according to claim 2, wherein the plurality of recording layers has lower magnetic resonance frequencies as the plurality of recording layers are father apart from the oscillation layer of the spin-torque oscillator.

4. The apparatus according to claim 2, wherein the controller writes data in the plurality of recording layers in descending order of the magnetic resonance frequencies.

5. The apparatus according to claim 1, wherein the controller writes data in the recording unit after reading data recorded in the recording unit.

6. The apparatus according to claim 1, wherein at least one of the plurality of recording layers comprises an antiferromagnetically coupled film.

7. The apparatus according to claim 1, further comprising an electric current source which supplies the electric current.

8. The apparatus according to claim 1, comprising a plurality of recording units.

9. The apparatus according to claim 1, comprising a plurality of memory cells each including the spin-torque oscillator and the recording unit, and the recording unit further includes at least one reference layer.

10. The apparatus according to claim 9, wherein at least one of the at least one reference layer comprises an antiferromagnetically coupled film.

11. The apparatus according to claim 9, further comprising a read bias generator to read data recorded in the recording unit.

12. The apparatus according to claim 1, wherein the spin-torque oscillator is stacked on the recording unit with an insulator layer being interposed therebetween.