Domain wall dispersions: Relaxation and resonance in Ni-Zn ferrite doped with V2O3

The complex permeability dispersions: relaxation and resonance are investigated in the Ni0.7Zn0.3Fe2O4 ferrites doped with V2O3 at different weight percent. The complex permeability was measured at frequencies in the 30 kHz to 6 GHz range. The intragranular porosity plays an important role to distinguish between relaxation and resonant dispersion. The results obtained show that a tight grain size distribution leads to a resonant character, while a wide grain size distribution results in a mixed dispersion. The complex permeability results were modeled with the resonant RCL equivalent circuit formed by a series RL arrangement in parallel with a capacitor C. The experimental results and the model are in agreement. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3506716]