Microwave assisted magnetic recording system

Patent metadata

Field	Value
Publication number	US-9449618-B2
Application number	US-42753409-A
Country	US
Kind code	B2
Filing date	Apr 21, 2009
Priority date	Apr 21, 2008
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

A microwave assisted magnetic recording system includes a write pole that generates a write magnetic field, an element that generates a radio frequency assist magnetic field, and a recording medium that moves relative to the write pole. The recording medium is exposed to the radio frequency assist magnetic field before it is exposed to the write magnetic field. One possible element that generates the radio frequency assist magnetic field is an assist wire placed perpendicular to the write pole. Alternatively, the assist wire can be placed parallel to the write pole so that its radio frequency assist magnetic field couples with the write pole, which in turn generates its own coupled radio frequency magnetic field along with the write magnetic field.

First claim

The invention claimed is:

1. A system comprising:
a write pole that generates a write magnetic field;
a write assist element that generates a substantially circularly polarized radio frequency (RF) assist magnetic field such that precession of magnetization in the write pole causes the write pole to create a coupled radio frequency assist magnetic field; and
a recording medium that moves relative to the write pole, where the recording medium is subjected to the coupled RF assist magnetic field of the write pole prior to being subjected to the write magnetic field.

2. The system of claim 1 wherein a polarization of the polarized RF assist magnetic field is inversed after the recording medium is subjected to the write magnetic field.

3. The system of claim 1 wherein subjecting the recording medium to the coupled RF assist magnetic field lowers a coercivity of the recording medium before the recording medium is subjected to the write magnetic field.

4. The system of claim 1 wherein the substantially circularly polarized radio frequency assist magnetic field has a resonance frequency that remains substantially constant for a duration of a magnetization reversal that is greater than that associated with a resonance frequency of a linearly polarized RF assist magnetic field.

5. The system of claim 1 wherein the write assist element comprises an assist wire positioned parallel to the write pole adjacent a leading edge of the write pole.

6. The system of claim 1 wherein the write assist element radio frequency assist magnetic field couples to the write pole in a plane parallel to the recording medium.

7. The system of claim 1 wherein the recording medium has a anisotropy of up to 20 kOe.

8. A system comprising:
a write pole that generates a write magnetic field;
a recording medium that moves relative to the write pole; and
a write assist element that generates a radio frequency assist magnetic field that couples to the write pole in a plane parallel to the recording medium such that precession of magnetization in the write pole causes the write pole to create a coupled substantially circularly polarized radio frequency assist magnetic field and deliver the substantially circularly polarized radio frequency assist magnetic field to the recording medium.

9. The system of claim 8 wherein the recording medium is subjected to the coupled radio frequency assist magnetic field before it is subjected to the write magnetic field.

10. The system of claim 9 wherein the write assist element comprises an assist wire positioned on a leading edge of the write pole and parallel to the write pole.

11. The system of claim 9 , wherein
a polarization of the coupled radio frequency assist magnetic field is inversed after the recording medium is subjected to the write magnetic field.

12. The system of claim 8 wherein subjecting the recording medium to the coupled magnetic field lowers a coercivity of the recording medium before the recording medium is subjected to the write magnetic field.

13. The system of claim 8 wherein the coupled magnetic field has a resonance frequency that remains substantially constant for a duration of a magnetization reversal that is greater than that associated with a resonance frequency of a linearly polarized radio frequency assist magnetic field.

14. The system of claim 8 wherein the write assist element comprises an assist wire positioned adjacent a trailing edge of the write pole and parallel to the write pole.

15. The system of claim 8 wherein the recording medium has anisotropy of up to 20 kOe.

16. A system comprising:
a write assist element that generates a first radio frequency assist magnetic field that is substantially circularly polarized;
a write pole that generates a write magnetic field and, in response to magnetic precession of the write pole coupled with the first radio frequency assist magnetic field, generates a second radio frequency assist magnetic field, and wherein magnetic field gradients for the write magnetic field and the second radio frequency assist magnetic field are collocated; and
a recording medium that moves relative to the write pole, where the recording medium is subjected to the second radio frequency assist magnetic field prior to being subjected to the write magnetic field.

17. The system of claim 16 , wherein
a polarization of the polarized radio frequency assist magnetic field is inversed after the recording medium is subjected to the write magnetic field.

18. The system of claim 16 wherein
the write assist element comprises an assist wire positioned on a leading edge of the write pole and parallel to the write pole.

19. The system of claim 16 , wherein
the recording medium has anisotropy of up to 20 kOe.

Assignees

• Rivkin Kirill Aleksandrovich
• Tabat Ned
• Seagate Technology Llc

Inventors

• Rivkin Kirill Aleksandrovich
• Tabat Ned

Classifications

• G11B5/1278 Primary

  specially adapted for magnetisations perpendicular to the surface of the record carrier · CPC title

• G11B2005/001

  Controlling recording characteristics of record carriers or transducing characteristics of transducers by means not being part of their structure · CPC title