Effect of nickel doping on the electrical conductance properties of La0.67Ba0.33Mn1-xNixO3 (x=0 and 0.075) manganite

Abstract

The effect of nickel doping on the morphological and electrical properties of La0.67Ba0.33Mn1-xNixO3 (x = 0 and 0.075) manganite prepared by sol-gel process was undertaken. The morphology and grain size of these samples were carried out using scanning electron microscopy (SEM). Our samples have a homogeneous and porous morphology. The average grain size decreases from 130 nm (for x = 0) to 110 nm (for x = 0.075). Electrical measurements were investigated using conductance spectroscopy technique in 102–106 Hz and 80–320 K, frequency and temperature ranges, respectively. AC and DC conductance analysis indicate that both compounds exhibit a metal-semiconductor transition at TMS, which decreases from 240 to 220 K with Ni doping. From DC conductance study, conduction mechanism is found to be dominated by the small polaron hopping process at high temperature. Activation energy is deduced from the variation of conductance with temperature. This energy increases from 34 meV for x = 0–70 meV for x = 0.075. This behavior can be related to the reduction of the density of charge carriers with nickel concentration. The variation of the conductance with frequency follows Drude model.