Magnetic Properties and Structure of (Co100-xFex)50Pt50 Alloy Thin Films.

The magnetic properties of (Co100-xFex)50Pt50 (0 ≤ x ≤ 100) alloy thin films in conjunction with the structure are studied. The intrinsic perpendicular magnetic anisotropy constant Ku measured at room temperature increases with order parameter S and decreases with tetragonality c/a. This result is at variance with a calculation based on first-principle analysis at the order parameter S=1. Ku increases with S for all compositions. The estimated Ku values obtained by extrapolation to S=1 for (Co100-xFex)50Pt50 would be nearly the same for x from 0 to 56, but increases with x for x larger than 56. The present result is consistent with the theoretical one, provided that the temperature dependence of Ku is neglected.