Temperature dependent conductivity mechanisms observed in Pr2NiTiO6

TL;DR

This study investigates how conduction mechanisms in Pr2NiTiO6 change with temperature, revealing a transition from small polaron hopping to variable range hopping around 490 K through combined spectroscopic and electrical analyses.

Contribution

It provides the first detailed analysis of temperature-dependent conduction mechanism crossover in Pr2NiTiO6 using multiple spectroscopic and electrical techniques.

Findings

Crossover from small polaron to variable range hopping at 490 K

Structural confirmation of monoclinic phase via XRD and Raman

Non-ideal relaxation behavior with distributed relaxation times

Abstract

The crossover between two different conduction mechanisms (variable range and small polaron hoppings) is probed utilizing a conjunction of thermally varying conductivity and impedance in polycrystalline Pr2NiTiO6 (PNT). A combination of X-ray diffraction (XRD) and Raman spectroscopic investigations authenticates the lower symmetric monoclinic structure for PNT. The conductivity, impedance and relaxation spectra highlight the combined contributions of the electrodes, grain-boundaries and grain microstructures to the carrier dynamics in PNT. The relaxation mechanism has a non-ideal nature with distribution of relaxation times as observed from the dielectric and impedance spectroscopic data. The dc resistivity investigation points towards a transition in the conduction mechanism showing a gradual crossover at temperature 490 K, from small polaron hopping to Mott s variable range hopping due to reduced activation energy.