Fe–Ta–C soft underlayer for double-layered perpendicular recording media

We report the investigation of microstructure, magnetic domain structure, and magnetic properties of Fe–Ta–C thin films for the application of soft underlayer (SUL) of perpendicular magnetic recording (PMR) media. As-deposited Fe80Ta8C12 film showed an amorphous structure with low saturation magnetization (MS∼600emu∕cc) and high coercivity (HC∼18Oe), while the optimally annealed (⩽500°C) films exhibited high value of MS (∼1350emu∕cc) and low HC (∼0.3Oe). The magnetic domain structures and their correlation with the microstructures suggest that the refinement of the average α-Fe grain size below 15nm and the magnetic properties of the intergranular residual amorphous matrix are very important in obtaining improved soft magnetic properties. These results indicate that Fe–Ta–C films would be a suitable candidate for SUL of FePt PMR media, for which the annealing for L10 ordering is essential.