DIAGNOSTICS OF COLOSSAL MAGNETORESISTANCE MANGANITE FILMS BY RAMAN-SPECTROSCOPY

Polarized Raman scattering by phonons is used to characterize thin fil ms prepared by laser ablation of La1-xCaxMnO3 targets. It was found th at, in the temperature range from 6 to 300 K, phonon spectra of La0.7C a0.3MnO3 films exhibit observable differences from those in bulk mater ials (microcrystalline ceramics and single crystals). A significant di fference was found in the spectra of ''as-grown'' films compared to th ose annealed in oxygen at 800 degrees C. The observed Raman peaks and their linewidths exhibit an irregular temperature dependence near T-c. A correlation of Raman data with magnetization of the sample was also found. (C) 1998 American Institute of Physics. [S0003-6951(98)03048-4 ].