Multi-frequency microwave assisted magnetic recording apparatus and method

Patent metadata

Field	Value
Publication number	US-9640203-B1
Application number	US-201615051083-A
Country	US
Kind code	B1
Filing date	Feb 23, 2016
Priority date	Feb 23, 2016
Publication date	May 2, 2017
Grant date	May 2, 2017

Abstract

An apparatus comprises a recording transducer configured for microwave-assisted magnetic recording (MAMR) and a magnetic recording medium. The recording transducer comprises a write pole configured to generate a write magnetic field and a write-assist arrangement proximate the write pole. The write-assist arrangement is configured to generate a radio frequency assist magnetic field at a plurality of different frequencies. The magnetic recording medium comprises a plurality of tracks, wherein adjacent tracks of the medium have different ferromagnetic resonant frequencies.

First claim

What is claimed is:

1. An apparatus, comprising:
a recording transducer configured for microwave-assisted magnetic recording (MAMR), comprising:
a write pole configured to generate a write magnetic field; and
a write-assist arrangement proximate the write pole and configured to generate a radio frequency assist magnetic field at a plurality of different frequencies; and

a magnetic recording medium comprising a plurality of tracks, wherein adjacent tracks of the medium have different ferromagnetic resonant frequencies.

2. The apparatus of claim 1 , wherein the write-assist arrangement comprises a single spin torque oscillator configured to selectively generate the assist magnetic field at each of the plurality of different frequencies.

3. The apparatus of claim 1 , wherein the write-assist arrangement comprises a plurality of spin torque oscillators each configured to generate the assist magnetic field at one of the plurality of different frequencies.

4. The apparatus of claim 1 , wherein:
the medium comprises a plurality of successive tracks each having a different ferromagnetic resonant frequency; and
the write pole is configured to generate a write field having a cross-track width that extends across at least a portion of the plurality of the successive tracks.

5. The apparatus of claim 1 , wherein the write pole is configured to generate a write field having a cross-track width that extends over 2N−1 tracks, where N is a number of successive tracks.

6. The apparatus of claim 1 , wherein the write-assist arrangement is configured to generate the assist magnetic field at two different frequencies.

7. The apparatus of claim 1 , wherein the write-assist arrangement is configured to generate the assist magnetic field at more than two different frequencies.

8. The apparatus of claim 1 , wherein the plurality of tracks comprise discrete tracks.

9. The apparatus of claim 1 , wherein the plurality of tracks comprise bit patterned tracks.

10. An apparatus, comprising:
a recording transducer configured for microwave-assisted magnetic recording (MAMR), comprising:
a write pole configured to generate a write magnetic field; and
a write-assist arrangement proximate the write pole and configured to generate a radio frequency assist magnetic field at a plurality of different frequencies, the plurality of different frequencies corresponding to different ferromagnetic resonant frequencies of different tracks of a magnetic recording medium.

11. The apparatus of claim 10 , wherein the write-assist arrangement comprises a single spin torque oscillator configured to selectively generate the assist magnetic field at each of the plurality of different frequencies.

12. The apparatus of claim 10 , wherein the write-assist arrangement comprises a plurality of spin torque oscillators each configured to generate the assist magnetic field at one of the plurality of different frequencies.

13. The apparatus of claim 10 , wherein the write-assist arrangement is configured to generate the assist magnetic field at two different frequencies.

14. The apparatus of claim 10 , wherein the write-assist arrangement is configured to generate the assist magnetic field at more than two different frequencies.

15. The apparatus of claim 10 , wherein the write pole is configured to generate a write field having a cross-track width that extends over 2N−1 tracks, where N is a number of successive tracks of a magnetic recording medium.

16. An apparatus, comprising:
a magnetic recording medium configured for microwave-assisted magnetic recording (MAMR) and comprising a plurality of tracks;
wherein adjacent tracks of the medium have differing ferromagnetic resonant frequencies.

17. The apparatus of claim 16 , wherein the plurality of tracks comprise discrete tracks.

18. The apparatus of claim 16 , wherein the plurality of tracks comprise bit patterned tracks.

19. The apparatus of claim 16 , wherein each track comprises magnetic material having one of two different ferromagnetic resonant frequencies.

20. The apparatus of claim 16 , wherein each track comprises magnetic material having one of three or more different ferromagnetic resonant frequencies.

21. A method, comprising:
moving a recording transducer configured for microwave-assisted magnetic recording (MAMR) relative to a magnetic recording medium comprising a plurality of tracks, wherein adjacent tracks of the medium have differing ferromagnetic resonant frequencies;
generating a radio frequency write-assist field having one of a plurality of different frequencies;
selecting a particular frequency that corresponds to a ferromagnetic resonant frequency of a particular track of the medium; and
generating a write field to write information to the particular track assisted by the write-assist field.

22. The method of claim 21 , wherein:
writing a first track having a first ferromagnetic resonant frequency comprises encroaching into a second track adjacent the first track without disrupting information written to the second track; and
writing a second track having a second ferromagnetic resonant frequency comprises encroaching into the first track without disrupting information written to the first track.

Assignees

• Seagate Technology Llc

Inventors

• Buch Bruce Douglas
• Lee Kim Yang
• Li Ning

Classifications

• G11B5/3909 Primary

  Arrangements using a magnetic tunnel junction · CPC title

• G11B2005/0024

  Microwave assisted recording · CPC title

• G11B5/02 Primary

  Recording, reproducing, or erasing methods; Read, write or erase circuits therefor · CPC title

• G11B5/3146

  magnetic layers · CPC title

• G11B5/743

  Patterned record carriers, wherein the magnetic recording layer is patterned into magnetic isolated data islands, e.g. discrete tracks · CPC title