Existence of Nearest Neighbor and Variable Range Hopping in Pr$_2$ZnMnO$_6$

Abstract

A joint investigation of X-ray diffraction (XRD) pattern and Raman spectrum authenticate the double phase monoclinic P21/n and cubic Fd-3m structures of polycrystalline Pr2ZnMnO6 (PZM). The existence of two different conduction mechanisms (Nearest neighbor hopping and Motts variable range hopping) is observed using a combined study of conductivity, dielectric relaxation and impedance spectra in PZM. This investigation point towards a transition from nearest neighbor hoping to Motts variable range hopping mechanism due to lowering activation energy around 580 K. The charge carriers hopping between the localized acceptor states at the grain boundaries (GBs), which dominants conduction mechanism below 580 K. The ac conductivity, dielectric relaxation, Nyquist plot, and electric modulus highlight the blended effect of grains (Gs) and GBs leads to the charge carrier dynamics in PZM. The dielectric relaxation and modulus formalism are analyzed on the basis of empirical Cole-Cole model. The conduction mechanism is found to be highly correlated with the relaxation mechanism and impedance spectroscopy.Comment: 15 page