Charge ordering and local structure in manganese oxide perovskites studied by EXAFS

Doped manganese oxide perovskites have attracted a great research interest for their peculiar magneto transport properties originating from a delicate and fascinating interplay between structural magnetic and electron transport properties. In the composition range 0.5 < x < 0.85 the La1-xCaxMnO3 solid solutions are paramagnetic insulators at high temperature and undergo, on cooling, a charge-ordering (CO) transition. This work exploits the extended X-ray absorption fine structure (EXAFS) technique to probe the evolution of the local structure around Mn ions, as a function of temperature, in a La0.33Ca0.67MnO3 sample. EXAFS results reveal an anomalous discontinuity in the structural evolution of MnO6 octahedra across the CO temperature pointing out the enhancement of static distortions in the low temperature CO phase.