Magnetic-field-induced multiple electronic states inLa0.5Ca0.5MnO3+δ

Abstract

We have observed multiple electronic states in the presence of a magnetic field in the half-doped ${\mathrm{La}}_{0.5}{\mathrm{Ca}}_{0.5}\mathrm{Mn}{\mathrm{O}}_{3+\delta }$ system. The resistivity of each state differs from one another by at least one order of magnitude. Application of a magnetic field induces first-order phase transitions among these states. A maximum ${10}^9$-fold magnetoresistance ratio has been observed at 4.2 K between the least and the most conductive phases. Our results differ from early observations that there is only one metal-to-insulator (two states) transition in other related half-doped systems.