Influence of Cr substitution on structural, magnetic and electrical conductivity spectra of LaFeO3

LaFe1-xCrxO3 of x = 0.0, 0.1, 0.3 and 0.5 is synthesized by the sol-gel citrate combustion method. X-ray diffraction (XRD) and Raman spectra measured at room temperature were influenced simultaneously by both substitution and crystallite size effect. The unusual Raman modes at similar to 676 cm(-1) arise as a result of Cr substitution in LaFeO3. The M (H) curve measured at 300 K and 5 K observed to show a weak ferromagnetism in Cr substituted LaFeO3. The temperature dependent investigation shows irreversibility in the FCC-ZFC curve due to antiferromagnetism and ferromagnetism (AFM\FM) exchange interaction. In LaFeO3, the Cr substitution enhances the interaction of Cr-O-Cr, observed as a transition in FCC-ZFC curve for LaFe0.7Cr0.3O3 and LaFe0.5Cr0.5O3 at similar to 117 K. Electrical conductivity spectra sigma'(f) measured between 100 Hz-1 MHz exhibit a double power law, on Cr substitution and temperature variation the double power law transforms to single power law. The dc conductivity activation energy shows the carrier type exhibit in the samples. (C) 2015 Elsevier B.V. All rights reserved.