O(Mn) vibrational bands in double-layered manganites: First and second order Raman scattering

PANTOJA AE, TRODAHL HJ, FAINSTEIN A, PREGLIASCO RG, BUCKLEY RC, BALAKRISHNAN G, LEES MR, PAUL DM

PHYSICAL REVIEW B - SOLID STATE

Año: 2001 vol. 63 p. 132406 - 132406

0556-2805

The Raman spectra of a number of the colossal magnetoresistance manganites and related systems are shown to display strong broad vibrational bands in both first and second order. The modes derive from the entire phonon branch involving the vibration of the oxygen ions in the MnO2 planes, ions which participate in Jahn-Teller displacements. The strength and temperature dependence of the second-order signal are shown to follow from conventional resonance scattering; they do not support the model that invokes Frank-Condon scattering.