Structure effect on the polarons in La/sub 0.7/Ca/sub 0.3-x/Ba/sub x/MnO/sub 3/ manganites

Summary form only given. Electron-phonon interaction plays a significant role in forming of colossal magnetoresistance effect (CMR). A local probe as given by the extended X-ray absorption fine structure (EXAFS) is an useful tool to study the polaronic charge and it variation on temperature and ionic size. Here we present a study of polaronic charge and its variation at the concentration structural orthorhombic (x=0; 0.03; 0.06)-rhombohedral (x=0.09; 0.12; 0.3) phase transition in La/sub 0.7/Ca/sub 0.3-x/Ba/sub x/MnO/sub 3/ manganites by Mn K-edge EXAFS measurement on single phase powders synthesized by solid state reaction method. EXAFS spectra were analyzed by the conventional method and using the regularization technique the atomic pair distribution functions (PDF) for Mn-O distances were obtained.