Temperature and frequency effect on charge transport in Pr0.5Ca0.5MnO3.

The polycrystalline ceramic manganite Pr 0.5 Ca 0.5 MnO 3 has been synthesized with conventional solid-state reaction route and its structural, magnetic and electrical behavior was explored experimentally in terms of change in thermoelectric and magnetic properties around a specific temperature. Structural investigation through XRD confirms that sample is single phase. Magnetic study reveals that the sample is charge ordered manganite (CO ≈ 250 K). The Magnetic behavior show alignment of Mn spins due to ferromagnetic behavior at 148 K (T C). Furthermore, in M(H) curve, a non-linear conduct was observed around 220 K and magnetic moment alignment is argued with respect to temperature. The response of applied frequency, using impedance spectroscopy, was studied for change in relaxation progressions. Equivalent circuit model (RQ) was implemented for getting impedance values. These impedance values helped us for determining the resistance and capacitance of grain and grain boundaries. Using calculated electrical features for a range of temperatures confirmed a variation in the conduction system at T C = 148 K, using small polaronic hopping model (SPH) and in light of Mott's variable range hopping model (MVRH). With MVRH, it is also discussed that carriers would hop to large distance with the help of activation energy below T C and above this these carriers are being facilitated by various trap centers via SPH. Dispersion around 148 K in dielectric relaxation and one sort of polarization is close to relaxation calculated from grain boundaries. [ABSTRACT FROM AUTHOR]