Perpendicular magnetization reversal mechanism of functional FePt films for magnetic storage medium

Magnetization reversal mechanism and related surface morphology of functional FePt(001) alloy films with large perpendicular magnetic anisotropy have been explored by alternate-atomic-layer deposition onto Pt/MgO(100) substrates via electron beam evaporation, and all evaporated films have been kept at in-situ substrate heating temperature of 400 degrees C. The FePt alloy film was composed of ultrathin [Fe (0.5 nm)/Pt (0.5nm)](n) Fe/Pt multilayer structures. The corresponding thickness of multilayer films was controlled by the periodic bilayer numbers (n) and varied in the range from 15nm (n = 15) to 30nm (n = 30). The surface topography was observed and varied from granular-like island to continuous microstructures with increasing the periodic numbers of Fe/Pt bilayer films. The measurement of angular dependent coercivity showed a tendency of the near rotation of reverse-domain type (n = 15) shift towards the domain-wall motion as a typical peak behavior (n = 30) with increasing the periodic bilayer numbers of Fe/Pt multilayers. On the basis of all magnetic measurements and corresponding magnetization analysis, indicating that the perpendicular magnetization reversal mechanism and related surface morphology of ordered FePt(001) alloy films could be systematically controlled by varying the periodic bilayer numbers accompanied with the thickness dependence. (C) 2014 The Japan Society of Applied Physics