Effect of Zn substitution in (111)-textured ZnxFe3−xO4 thin films on magnetization dynamics

Abstract

The strong (111)-textured ZnxFe3−xO4 thin films were grown on SiO2-terminated silicon substrates using pulsed laser deposition. X-ray diffraction and high resolution transmission electron microscopy clearly show the column growth structure along the film thickness direction in [111] crystalline orientation for every grain column. With the introduction of texture induced magnetic anisotropy in the free energy density model, we quantitatively determined the doping effect on the various anisotropies in (111)-textured ZnxFe3−xO4 films. The mechanisms of ferromagnetic resonance linewidth of ZnxFe3−xO4 thin films are investigated by the theoretical fitting, in which considering the contributions from intrinsic spin-orbit coupling, extrinsic compositions from two-magnon scattering and inhomogeneous broadening. It is found that the Gilbert damping coefficient α increases with increasing Zn substitution x from 0 to 0.3, indicating that the spin-orbit coupling of the ZnxFe3−xO4 thin films increases with the introduction of Zn impurities.