Permanent magnet assisted magnetic recording
US10699731B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 17, 2019 |
| Grant date | Jun 30, 2020 |
| Priority date | — |
| Expiry date | Jan 17, 2039 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/6082
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A perpendicular magnetic recording writer is disclosed with a permanent magnet (PM) formed within a write gap (WG) that is between a main pole (MP) trailing side and a trailing shield. The PM has a magnetization that is anti-parallel to a WG field (HWG) when a transition is written thereby enhancing the MP field on a magnetic bit, and generates a PM field that assists the MP field. When HWG becomes saturated after the transition is written and exceeds PM coercivity that is from 500 Oe to 8000 Oe, PM magnetization flips to an opposite direction and reduces the MP field thereby improving adjacent track erasure. The PM may be at the air bearing surface (ABS) or recessed up to 50 nm from the ABS, and has a down-track thickness less than the WG thickness, and a cross-track width≤to the track width of the MP trailing side.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.