Nanoscale Phase Separation and Colossal Magnetoresistance

Condensed matter is one of the most active areas of research in physics. Ev­ ery year new materials are discovered with properties that are as challenging as or more than those of the year before. The effort is led mainly by exper­ imentalists, who systematically manage to prepare compounds with exotic new properties, including complex ground states involving nontrivial spin, charge, lattice, and orbital arrangements. This work is typically carried out by a relatively small number of researchers, compared with other disciplines, and the interaction between experimentalists and theorists is quite strong. It is a real pleasure for a theorist, like the author, to have experimental data with which to test proposed ideas in short time scales. This allows for a theory-experiment cross-fertilization that keeps the field very active. These are quite interesting times in condensed matter for sure. This book is devoted to the study of a family of materials known as man­ ganites. As for other exotic compounds, the fast development of experiments has induced a rapid evolution of the main theoretical ideas. A considerable ef­ fort, both on theory and experiments, has led to the currently much-accepted notion that nanoscale phase separation is at the heart of the behavior of elec­ trons in these compounds. This point is described in detail in this book, with a plethora of experimental data, computer simulation results, and analytic calculations supporting that description.

The study of the spontaneous formation of nanostructures in single crystals is rapidly developing into a dominant field of research in the subject area known as strongly correlated electrons. The structures appear to originate in the competition of phases. This book addresses nanoscale phase separation, focusing on the manganese oxides with colossal magnetoresistance (CMR). The text argues that nanostructures are at the heart of the CMR phenomenon. Other compounds are also addressed, such as high-temperature superconductors, where similar nanostructures exist. Brief contributions by distinguished researchers are also included. The book contains updated information directed at experts, both theorists and experimentalists. Beginning graduate students or postdocs will also benefit from the introductory material of the early chapters, and the book can be used as a reference for an advanced graduate course.