Effect of microstructure on the magnetic properties of L1 CoPt–20 at. %C magnetic thin film

Abstract

Effect of microstructure on the magnetic properties of monolithic L10 CoPt–20 at. %C granular film was investigated by intercalating the carbon layer in the form of CoPt/Cn (n=1,4) using magnetron sputter deposition. A micromagnetics simulation was also performed to calculate the effect of microstructure on the magnetic hysteresis loop. The carbon was observed to dissolve into the ordered CoPt lattice and to increase the c/a ratio; the amount of dissolution increases with decreasing carbon single layer thickness due to the capillarity effect. The carbon dissolution reduces the effective magneto-crystalline anisotropy constant of the ordered CoPt(C) granular film because of the increasing c/a ratio and of the reduced ordering kinetics. The slope of the hysteresis loop varied with the amount of carbon dissolution, which is primarily related to the grain size variation with the amount of carbon dissolution together with the presence of untransformed disordered phase in the film.