Evidence for a local lattice distortion in Ca-doped LaMnO3

We have found that a significant change in the local structure of La2/3Ca1/3MnO3 occurs between 80 K and temperatures above the Curie temperature, T-c=270 K. Near-edge x-ray-absorption spectra exhibits changes between 80 K and above T-c. X-ray-absorption fine structure reveals differences between the nearest-neighbor Mn-O bond distributions at 80 K and above T-c. The single-site distribution at low temperature becomes a complex, multi-site distribution above T-c. The observed change is consistent with proposed small polaron related local Jahn-Teller distortions for T>T-c.