Multi-scale Phase Modulations in Colossal Magnetoresistance Manganites

Extensive experimental results are presented on the multi-scale phase modulation phenomena observed in colossal magnetoresistance manganites. Two key types of phase inhomogeneities directly relevant to the colossal magnetoresistance (CMR) are discussed. The first type involves micrometer-scale coexistence of structurally and electronically different phases. We present extensive experimental data for a prototypical system exhibiting such a phase coexistence, (La,Pr)5/8Ca3/8MnO3. These data reveal that percolative transport phenomena play the key role in the metal-insulator transition in this system, and are largely responsible for the significant magnitude of the magnetoresistance. The phase