Anomalous electrical relaxation and polaron conduction in nano-crystalline Mn0.5Zn0.5Fe2O4

Nano-crystalline Mn0.5Zn0.5Fe2O4 was synthesized by chemical co-precipitation method and characterized with X-ray diffraction. Ac electrical impedance data are taken for the frequency range of 1Hz to 1MHz for various temperatures from 303K to 483K. The ac electrical conduction deviates from the Debye type relaxation which indicates polaron type conduction. In the present study unique anomalous relaxation function in time and frequency domain is used to investigate deviation from the Debye relaxation. The physical basis of anomalous or non-Debye process is explained in terms of change in Debye dipole μD=ρrD of charge ρ into gρ due to the molecular charge interaction and defect disorder. This interaction shifts the Debye relaxation rate τ to a slow relaxation rate τg. The fraction 0