On the relationship of high coercivity and L1(sub 0) ordered phase in CoPt and FePt thin films

Research was conducted to study the microstructure and the room-temperature hysteretic magnetic characteristics of sputtered, 10 nm thin films of equiatomic binary alloys of CoPt and FePt using transmission electron microscopy (TEM) and a superconducting quantum interference device magnetometer. Dark-field TEM images were digitally analyzed to characterize transformation from an atomically disordered, face-centered-cubic structure to the L1(sub 0) ordered structure. It has been concluded that a direct relationship exists between the ordered volume fraction and the coercivity, with the maximum value of the coercivity coinciding with the fully ordered structure.