METHOD AND DEVICE FOR AC DEMAGNETIZATION FOR MAGNETIC RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To ship perpendicular magnetic recording media in the AC demagnetized state of best recording characteristics in the short-time demagnetization of magnetization recorded on the recording layers of the media by certifying test when the perpendicular magnetic recording media are mass-produced.;SOLUTION: In a certifying test device, separately from magnetic head 4, a certifying zone batch magnetic field application means 10-1 and a uniaxial stage 41 for moving this means 10-1 in an up-and-down Z direction to serve as an AC demagnetization device 01. The means 10-1 uses a permanent magnet as a magnetomotive force source, has N and S magnetic poles arrayed in a disk rotational direction sandwiching a gap alone a radial path over a certifying zone including all recording zones from an inner diameter side to an outer diameter side on the surface of a magnetic disk 2, facing the disk surface from above, and applies a demagnetizing magnetic field returning through the disk surface on the disk surface of the radial path. When the means 10-1 brought close to the disk surface is gradually set apart during disk rotation, an alternating magnetic field gradually reduced is applied on the disk full surface to execute AC demagnetization.;COPYRIGHT: (C)2006,JPO&NCIPI