Effects of iron concentrations on the electrical properties of La0.67Ba0.33Mn1−xFexO3

Abstract

• Introducing iron in LBMO system decreases electrical conductance. • The material turns from metallic into semi-insulating behavior when increasing Fe concentration. • The value x = 0.10 represents the limit of Fe concentrations which destroys metallic-insulating transition. • Under polarization, the conductance of the material increases and activation energy decreases for all Fe concentrations. In order to study the electrical properties of the samples La 0.67 Ba 0.33 Mn 1− x Fe x O 3 , transport measurements have been performed on this compound using admittance spectroscopy technique. For all temperatures the DC conductance decreases when increasing Fe content and x = 0.10 represents the limit value of Fe concentration which destroys metallic-insulating transition. From DC conductance study, electronic conduction is found to be dominated by thermally activated hopping. Activation energy is deduced from the variation of conductance with temperature. This energy increases with increasing Fe content from E a = 27 meV for x = 0 to E a = 154 meV for x = 0.20. The AC conductance spectrum is found to obey Jonscher universal power law. The exponent “ n ” changes with Fe concentration ( n ≈ 1 for x = 0.20 and n = 0 for x = 0). This indicates that the material evolves from metallic to semi-insulating behavior when increasing Fe content. Under polarization, the conductance of the material increases and activation energy decreases for all Fe concentrations.