Jahn-Teller phonon anomaly and dynamic phase fluctuations in La0.7Ca0.3MnO3

Inelastic neutron scattering was used to study the temperature (T) dependen ce of the lattice excitations in La0.7Ca0.3MnO3. An optical Jahn-Teller pho non exhibits continuous but anomalous damping with increasing temperature i n the ferromagnetic-metallic phase and collapses above the Curie temperatur e Te (240 K). We attribute this anomaly to the growing dynamic phase segreg ation as T --> T-C, thus providing evidence of local fluctuations associate d with the short-range polaron or charge/orbital ordering in the ferromagne tic-metallic state.