Reverse magnetic reset to screen for weakly pinned heads
US7138797B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 2004 |
| Grant date | Nov 21, 2006 |
| Priority date | — |
| Expiry date | Sep 30, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2005/0016
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method is disclosed for testing pinned layers of magnetic disk drive read heads having at least one pinned layer, where the magnetic orientation of the pinned layers has been set in an initial direction. The method includes applying a large magnetic test field at a reverse canted reset angle. First test responses from the disk drive read heads are then measured in a small magnetic test field. A large magnetic test field is applied at normal canted reset angle. The disk drive heads are then subjected to a full suite of performance tests in a small magnetic test field to verify their acceptability. These second test responses are then compared to the first test responses to identify read heads having weakly pinned layers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.