Raman scattering has been investigated for a single crystal of Sm1-xSrxMnO3 (x = 0.45), which shows prototypical colossal magnetoresistance (CMR), and related crystals. The emergence of broad phonon bands indicates dynamical charge/orbital correlation above the Curie temperature. Such a feature is systematically enhanced with a decrease of one-electron band width toward the orbital order-disorder phase boundary, being concomitant with the enhancement of CMR. The charge/orbital correlation affected by charge/orbital ordering instability is likely to be responsible for the steep insulator-metal transition and CMR.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics