We report Mn K-edge extended x-ray absorption fine structure spectra on La0.75Ca0.25MnO3 up to high momentum transfer across the metal-insulator (M-I) transition. The data show compelling evidence for (i) large or intermediate Jahn-Teller polarons (IJTP), characterized by an anomalous longer Mn-O bond (Δ R = 0.09 Å) in the metallic phase (T 170K, characterized by a longer Mn-O bond (Δ R = 0.21 Å), which coexist with the IJTP above the M-I transition and has equal probability in the temperature range of colossal magnetoresistance. © 1998 The American Physical Society.
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