Ac study of 10% Fe-doped La0.65Ca0.35MnO3 material by impedance spectroscopy

The ac electrical properties of La0.65Ca0.35Mn0.90Fe0.10O3 polycrystalline sample have been investigated by complex impedance analysis over the frequency and temperature ranges of 1-100 kHz and 77-323 K, respectively. Around the metal-insulator transition temperature capacitative effect has been observed which may be due to clustering of defects induced by iron doping. The impedance plane plot shows semicircle at different temperatures and an equivalent circuit, R-1(R2C), i.e., a resistor-capacitor, has been proposed to explain the impedance results. The correlated barrier hoping (CBH) model is found to be more appropriate for explaining the frequency and temperature dependent ac-conductivity data.