High power ratio mode for TAMR drives

Patent metadata

Field	Value
Publication number	US-10679653-B1
Application number	US-201916296366-A
Country	US
Kind code	B1
Filing date	Mar 8, 2019
Priority date	Mar 8, 2019
Publication date	Jun 9, 2020
Grant date	Jun 9, 2020

Abstract

A method of operating a HDD having a read/write head configured for Perpendicular Magnetic Recording (PMR) and configured for use in Thermally Assisted Magnetic Recording (TAMR). By using selected settings of a power ratio (PR) value to ensure that accurate fly height (FH) measurements of head-disk interference (HDI) can be taken during write touchdowns (TDs), head damage can be eliminated during HDI events. Under normal operating conditions the PMR head develops a sharp protrusion due to heating from the TAMR apparatus as well as the write current and read and write heaters. The sharp protrusion is prone to striking the disk surface, instead of the shields doing so. The shields would be more capable of absorbing the HDI, which would allow the HDI sensors (HDIs) to provide a more sensitive reading of the HDI which would prevent head wear caused by the sharp protrusion. By adjusting the power ratio (PR) to be at least the turning point (TP) value, the write shield will approach the disk surface before the sharp protrusion.

First claim

What is claimed is:

1. A method for operating a PMR read/write head configured for Perpendicular Magnetic Recording Thermally Assisted Recording (PMR TAMR), comprising:
providing PMR read/write head configured for TAMR and a TAMR apparatus for supplying optical power;
said PMR read/write head including read and write shields formed, respectively adjacent to said read head and said write head; wherein
said PMR further includes at least one read heater (Hr) formed adjacent to said read head and at least one write heater (Hw) formed adjacent to said write head, said Hr and Hw being configured for being supplied power independently; wherein
said PMR further includes at least one head-disk interference sensor (HDIs); wherein
a narrow write gap is formed at an ABS of said write head; then,
choosing a value of a power ratio, PR, where PR=([Hr power]/[(Hr power)+(Hw power)])*100%, to ensure that when a read or write touchdown occurs, said read shields and said write shields and said at least one HDIs will approach said disk surface to within a distance that will enable said HDIs to effectively and reliably signal said touchdown (TD) and will protect from wear a sharp protrusion of said write head caused by TAMR heating.

2. The method of claim 1 wherein said PMR read/write head configured for Perpendicular Magnetic Recording Thermally Assisted Recording (PMR TAMR) is mounted on a slider whereby said PMR read/write head is maintained at a flying height by aerodynamic properties of said slider when said slider is positioned above a rotating magnetic recording disk, but wherein said slider mounted PMR read/write head may undergo touchdowns (TD) which are required to be detected.

3. The method of claim 1 wherein during TD detection a large value of PR is used in a preheat mode wherein only said read and write heaters are operating and there is no writer current and a TAMR apparatus, which supplies optical power to said PMR read/write head, is not operative.

4. The method of claim 3 wherein said large value of PR is at least the turning point (TP) value, which is the mid-range value of PR.

5. The method of claim 1 wherein a large value of PR is used during write TD detection, where there is a writer current and said TAMR is operative.

6. The method of claim 4 wherein a value of PR=70% enables said HDIs to accurately detect TD and enables shields to prevent head wear to sharp protrusion caused by TAMR heating.

7. The method of claim 1 wherein said TAMR apparatus includes a source for supplying power in the form of electromagnetic radiation, a waveguide to transfer said electromagnetic radiation towards said ABS and a plasmon generator to produce plasmon modes by coupling to said electromagnetic radiation and to then direct near-field energy from said plasmon modes to a position on a rotating disk that is generally coincident to a region upon which said write head directs a magnetic flux.

8. A method for operating a slider-mounted PMR read/write head configured for Perpendicular Magnetic Recording Thermally Assisted Recording (PMR TAMR) in a hard disk drive (HDD), comprising:
providing a HDD including a rotatable hard disk, a slider-mounted PMR read/write head configured for TAMR and a TAMR apparatus; wherein
said PMR read/write head comprises a magnetically shielded read head and a magnetically shielded write head wherein read and write shields are formed, respectively adjacent to said read head and said write head; wherein
said slider is an aerodynamically configured prism that maintains said PMR read/write head at a flying height (FH) when positioned above a rotating magnetic medium; wherein
said slider-mounted PMR further includes at least one read heater (Hr) formed adjacent to said read head and at least one write heater (Hw) formed adjacent to said write head, said Hr and Hw being configured for being supplied power independently; wherein
said PMR further includes at least one head-disk interference sensor (HDIs); wherein
a narrow write gap is formed at an ABS of said write head, said write gap comprising a magnetic pole tip and a spot at which an optical near-field is emergent; then,
upon setting said hard disk into rotational motion, choosing a value of a power ratio, PR, where PR=([Hr power]/[(Hr power)+(Hw power)])*100%, to ensure that when a read or write touchdown occurs, said read shields and said write shields and said at least one HDIs will approach said disk surface to within a distance that will enable said HDIs to effectively and reliably signal said touchdown and will protect from wear a sharp protrusion of said write head caused by TAMR heating.

9. A read/write head configured for Perpendicular Magnetic Recording Thermally Assisted Recording (PMR TAMR), comprising:
said PMR read/write head comprises a read head portion and a write head portion; wherein
said PMR read/write head comprises read and write shields formed, respectively adjacent to said read head and said write head portions; wherein
said PMR read/write head further comprises at least one read heater (Hr) formed adjacent to said read head portion and at least one write heater (Hw) formed adjacent to said write head portion, wherein
said Hr and Hw are configured for being supplied power independently; wherein
said PMR read/write head further comprises at least one head-disk interference sensor (HDIs); wherein
said PMR read/write head is further configured for application of a power ratio, PR, where PR=([Hr power]/[(Hr power)+(Hw power)])*100%, whose value is chosen to ensure that when an intentional touchdown (TD) is made to occur, said read shields and said write shields and said at least one HDIs will approach a disk surface to within a distance that will enable said HDIs to clearly and reliably signal said touchdown and will also protect from wear a sharp protrusion of said write head caused by TAMR heating.

10. The read/write head configured for Perpendicular Magnetic Recording Thermally Assisted Recording (PMR TAMR) mounted on a slider, comprising:
the read/write head of claim 9 ;
a slider aerodynamically configured to support a PMR TAMR read/write head at a stable flying height (FH) above a rotating magnetic recording medium;
said read/write head mounted on said slider.

11. The slider-mounted PMR read/write head of claim 10 installed in a hard disk drive (HDD) configured for thermally assisted magnetic recording (TAMR) and further comprising a TAMR apparatus for supplying optical power to said write head.

12. The PMR read/write head of claim 9 wherein, during TD detection, a value of PR that is at least a turning point (TP) value is chosen and used in a preheat mode wherein only said read and write heaters are operating and there is no writer current and the TAMR is not operative.

13. The PMR read/write head of claim 9 wherein a large value of PR, that is at least the turning point (TP) value, is chosen and used during write TD detection, where there is a writer current and said TAMR is operative.

14. The PMR read/write head of claim 9 wherein a value of PR=70% can be chosen and used and said value enables said HDIs to accurately detect TD and enables shields to prevent head wear to sharp protrusion caused by TAMR heating.

15. The PMR read/write head of claim 9 wherein said TAMR configuration comprises a source for supplying power in the form of electromagnetic radiation, a waveguide to transfer said electromagnetic radiation towards an ABS and a plasmon generator to produce plasmon modes by coupling to said electromagnetic radiation and to then direct near-field energy from said plasmon modes to a position on a disk tha

Assignees

• Sae Magnetics Hk Ltd
• Headway Tech Inc

Inventors

• Zeng Qinghua
• Ngan Siu Yin
• Ka Soramany
• Cha Ellis

Classifications

• G11B5/4866 Primary

  the arm comprising an optical waveguide, e.g. for thermally-assisted recording · CPC title

• G11B5/6011

  Control of flying height · CPC title

• G11B5/1278 Primary

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

• G11B2005/0021

  Thermally assisted recording using an auxiliary energy source for heating the recording layer locally to assist the magnetization reversal · CPC title

• G11B5/6076

  Detecting head-disk contact · CPC title