Doping effects arising from Ni for Fe in PrFeO3 ceramic thin films

Abstract

Structural, morphological and transport properties of PrFe1− x Ni x O3 (x = 0.1, 0.2, 0.3, 0.4 and 0.5) thin films grown on LaAlO3 substrate by pulsed laser deposition were studied experimentally. Structural analysis of the samples showed that they have in-plane compressive strain and single-phase epitaxial growth along with c-axis (001) orientation having orthorhombic structure with space group Pbnm. The observed strain is reduced with Ni substitution. The resistivity as a function of temperature follows the variable range hopping (VRH) model up to certain amount of Ni substitution (x = 0.3) but fails for higher values of x. From the above model, parameters such as density of states at the Fermi level, N(E F), hopping energy, E h, and hopping distance R h, were calculated. Ni substitution leads to an increase in conductivity and this conduction is controlled by disorder-induced localization of charge carriers. With Ni substitution the gap parameter is found to decrease. The enhancement in conductivity and the failure of VRH model for higher doped compositions at high temperature is discussed.