Patent ID: 9355660
Filing Date: 2016-05-31
CPC Classification: G11B

Claim Text:
1. A testing method of a magnetic head, the magnetic head including a pair of hard magnets providing a longitudinal bias field and an air bearing surface, and the testing method comprising: (a) applying a first magnetic field with a constant intensity in a first direction that is the same with that of the longitudinal bias field to the magnetic head, simultaneously applying a second magnetic field with variant intensities in a second direction traversing the air bearing surface, and measuring a first noise which is generated in response to externally applied magnetic fields; (b) applying a third magnetic field with a constant intensity in a third direction that is opposite to the first direction to the magnetic head, simultaneously applying the second magnetic field with variant intensities in the second direction, and measuring a second noise which is generated in response to externally applied magnetic fields; and (c) analyzing a delta noise between the first noise and the second noise.