Post-deposition heat-treated NixZn1−xFe2O4 films exhibiting higher resonance frequency

The effect of thermal annealing with applying magnetic field on structural and magnetic properties has been investigated for NixZn1−xFe2O4 (x = 0.28 and 0.45) films deposited on Si(1 1 1) substrates by radio frequency magnetron sputtering. The post-deposition heat-treated ferrite films exhibited better soft magnetic properties that a slight increase in the saturation magnetization and decrease in the coercivity. The complex permeability μ = μ′ − iμ″ values of the ferrite films as-deposited and post-deposition heat-treated were measured at frequency up to 5 GHz. The results showed that the resonance frequency of the post-annealed ferrite films shifted to a higher frequency range, especially for x = 0.28 which increased from 1.8 GHz to 2.2 GHz.