Raman spectroscopy of orthorhombic La_1-xCa_xMnO₃,x= 0.1-0.3

Abstract

This paper reports polarization-resolved temperature-dependent Raman scattering measurements on single crystals of the orthorhombic perovskite colossal-magnetoresistive material La1-xCaxMnO3, with x = 0.1,0.275,0.3. It is demonstrated that two of the Raman lines undergo an anomalous softening as temperature is lowered through TC, related to the development of magnetic order below ambient temperature. Also reported is the presence of second-order scattering, as has been previously predicted for the manganites. Only the broad features at 500 and 650 cm-1 that arise from disorder-induced scattering contribute to the second-order signal.