We have measured high resolution Mn K-edge x-ray absorption near edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) to investigate the local atomic displacements in the MnO 6 octahedra and their importance to the colossal magnetoresistance in the La0.75Ca0.25MnO 3 system. A combined analysis of the XANES and EXAFS shows that the colossal-magneto resistance (CMR) transition is characterized by a transition from a phase of delocalized intermediate polarons to a phase showing coexistence of the intermediate and small polarons accompanied by the opening of a gap at E F due to Jahn Teller splitting of eg orbitals.
Spatial cross-over of polarons across the CMR transition in La0.TsCa0.2sMnO3 system
1999
Abstract
We have measured high resolution Mn K-edge x-ray absorption near edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) to investigate the local atomic displacements in the MnO 6 octahedra and their importance to the colossal magnetoresistance in the La0.75Ca0.25MnO 3 system. A combined analysis of the XANES and EXAFS shows that the colossal-magneto resistance (CMR) transition is characterized by a transition from a phase of delocalized intermediate polarons to a phase showing coexistence of the intermediate and small polarons accompanied by the opening of a gap at E F due to Jahn Teller splitting of eg orbitals.File in questo prodotto:
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