Thickness and angle dependence of the coercivity on highly uniaxial anisotropy FeTaN thin films

A set of single-layer FeTaN thin films with thickness ranging from 30 to 720 nm has been fabricated on silicon substrate by magnetron sputtering. Effort is focused on the dependence of the coercivity on the film thickness and on the angle of the external magnetic field applied. The rotation model has been used to calculate the angle dependence of the coercivity. It agrees well with the experimental polar plot of the coercivity when suitable values of the magnetocrystalline constant (K1) and the magnetoelastic constant (KS) are chosen. The change in shape of the polar plot of the coercivity with the thickness is attributed to the competition between the magnetocrystalline and magnetoelastic energies. The effect of grain size and stress to the coercivity is also discussed