Field- and temperature-controlled magnetic phase separation in (La0.25Pr0.75)(0.7)(Ca0.3MnO3)-O-18 manganite as seen by LaNMR and magnetization measurements

We present a detailed La NMR and magnetization study of (La0.25Pr0.75)(0.7) Ca0.3MnO3 manganite, in which an insulator-metal transition can be induced by magnetic field and also by oxygen isotope substitution. NMR results demo nstrate directly the presence of magnetic phase separation at a local level . The microscopic magnetic structure of the sample depends on cooling condi tions [namely, zero field cooling (ZFC) or field cooling (FC)] and can be c ontinuously controlled through the phase separation range by magnetic field and temperature. The magnetic phase diagrams of the sample have been obtai ned in a wide ranges of fields and temperatures for both ZFC and FC cases.