X-ray and neutron scattering measurements directly demonstrate the existence of polarons in the paramagnetic phase of optimally-doped colossal magnetoresistive oxides. The polarons exhibit short-range correlations that grow with decreasing temperature, but disappear abruptly at the ferromagnetic transition because of the sudden charge delocalization. The "melting" of the charge ordering as we cool through TC occurs with the collapse of the quasi-static polaron scattering, and provides important new insights into the relation of polarons to colossal magnetoresistance.
@article{arxiv.cond-mat/9907304,
title = {Charge melting and polaron collapse in $La_{1.2}Sr_{1.8}Mn_{2}O_{7}$},
author = {L. Vasiliu-Doloc and S. Rosenkranz and R. Osborn and S. K. Sinha and J. W. Lynn and J. Mesot and O. H. Seeck and G. Preosti and A. J. Fedro and J. F. Mitchell},
journal= {arXiv preprint arXiv:cond-mat/9907304},
year = {2009}
}
Comments
4 pages (RevTex), 3 postscript-formatted figures (Figs. 1 and 2 are color figures)