Order and dynamics of intrinsic nanoscale inhomogeneities in manganites

Abstract

Neutron elastic, inelastic, and high energy x ray scattering techniques are used to explore the nature of the polaron order and dynamics in the colossal magnetoresistive CMR system La0.7Ca0.3MnO3. Polaron correlations are known to develop within a narrow temperature regime as the Curie temperature is approached from low temperatures, with a nanoscale correlation length that is only weakly temperature dependent. The static nature of these short range polaron correlations indicates the presence of a glasslike state, very similar to the observations for the bilayer manganite in the metallic ferromagnetic doping region. In addition to this elastic component, inelastic scattering measurements reveal dynamic correlations with a comparable correlation length and with an energy distribution that is quasielastic. The elastic component disappears at a higher temperature T , above which the correlations are purely dynamic. These observations are identical to the polaron dynamics found in the bilayer manganite system in the CMR regime, demonstrating that they are a general phenomenon in the manganite