Micromagnetic analysis of L1 ordered FePt perpendicular recording media prepared by magnetron sputtering

A three-dimensional micromagnetic model is built up to analyze the relationship between the magnetic property and the microstructure of FePt thin films, with careful discussions of the tetragonal symmetry and the magnetostriction. It is found that the in-plane magnetoelastic effect with a residual tensile stress on the order of 1Gpa would enlarge the perpendicular coercivity and the saturation field of the longitudinal loop; the tetragonal anisotropy, such as tetragonal anisotropy with 5:1 in-plane∕out-of-plane anisotropy ratio, tends to enlarge the longitudinal coercivity and conduce the open up between the tails of the longitudinal and perpendicular loops. The high perpendicular squareness is caused by the perfect orientation of the c axis and large exchange interactions. The simulated M-H loops agree well with experiments.