Magnetic Properties of Patterned CGC Perpendicular Films With Soft Magnetic Fillings

To increase the areal density of hard disk drives (HDDs), discrete track media (DTM) and bit-patterned media (BPM) are being extensively studied. In the DTM and BPM, it is essential to isolate data tracks or bits. Unlike isolating the data tracks or bits using the conventional procedure involving physical etching, we attempted to isolate the tracks or bits with a soft guard band using an area-selective ion irradiation method. We prepared hard and soft (H/S) patterned films by nanoimprinting followed by ion irradiation. We confirmed the magnetic isolation of tracks and bits using magnetic force microscopy (MFM) images and magnetooptical Kerr effect (MOKE) signals. The results of an analysis of the magnetic properties of patterned coupled granular continuous (CGC) films with weak exchange coupling confirmed the validity of this novel approach for the fabrication of DTM and BPM.