Strain imaging of magnetic domain structures in the magnetic head of a hard disk drive

摘要

Detection and imaging of magnetic-field-induced strains using scanning probe microscopy enable us to observe magnetic domain structures. Domain structures in a magnetization reversal process of the lateral-recording head in a hard disk drive were investigated by scanning over the air-bearing surface of the head. External magnetic fields were applied by the writing coil. In the process, magnetic domains in the bottom pole were divided into right and left regions in the cross-track direction, having opposite magnetizations. The domain boundary moved to right or left according to writing currents, and vanished by larger currents than 15 mA. Hemispherical domain structures with a diameter of around 0.6 μm, consisting of two opposite magnetizations in the direction of the applied magnetic field, were observed in several portions of the bottom pole. The domain structures also vanished with increasing field strength.