THE EFFECT OF Fe SUBSTITUTION ON THE STRUCTURAL TRANSITION OF LaMn1-xFexO3 MANGANITES: A RAMAN SPECTROSCOPY STUDY

Abstract

We present results of Raman scattering studies on LaMn 1-x Fe x O 3+δ manganite over a wide range of doping content (x = 0.1 - 0.75). There is no previous Raman work on the LaMn 1-x Fe x O 3+δ manganite system. The analysis of Raman spectra of various doping contents allows us to identify a clear spectroscopic signature of structural change from orthorhombic to rhombohedral at x = 0.4 as x increases. At x = 0.4, both phases coexist. This result is in good agreement with our XRD results. The resistance vs. temperature relation indicates that there is no metal-insulator transition in these samples in the range of observed temperatures. No abrupt change in the peak frequencies is observed across the measured temperatures. This indicates that the structural changes are not spatially coherent, but local in nature.