Ba doped Fe₃O₄ nanocrystals: Magnetic field and temperature tuning dielectric and electrical transport

Nanocrystalline BaFe₂O₄ has been prepared through low temperature pyrophoric reaction method. The structural, dielectric and electrical transport properties of BaFe₂O₄ are investigated in detail. AC electrical properties have been studied over the wide range of frequencies with applied dc magnetic fields and temperatures. The value of impedance is found to increase with increase in magnetic field attributing the magnetostriction property of the sample. The observed value of magneto-impedance and magnetodielectric is found to ∼32% and ∼33% at room temperature. Nyquist plots have been fitted using resistance-capacitor circuits at different magnetic fields and temperatures showing the dominant role of grain and grain boundaries of the sample. Metal-semiconductor transition ∼403 K has been discussed in terms of delocalized and localized charge carrier.We have estimated activation energy using Arrhenius relation indicating temperature dependent electrical relaxation process in the system. Ac conductivity follow a Jonscher's single power law indicating the large and small polaronic hopping conduction mechanism in the system. (paper)