Field- and temperature-controlled magnetic phase separation in $({\mathrm{La}}_{0.25}{\mathrm{Pr}}_{0.75}{)}_{0.7}{\mathrm{Ca}}_{0.3}{\mathrm{Mn}}^{18}{\mathrm{O}}_3$ manganite as seen by La NMR and magnetization measurements

We present a detailed La NMR and magnetization study of $({\mathrm{La}}_{0.25}{\mathrm{Pr}}_{0.75}{)}_{0.7}{\mathrm{Ca}}_{0.3}{\mathrm{MnO}}_3$ manganite, in which an insulator-metal transition can be induced by magnetic field and also by oxygen isotope substitution. NMR results demonstrate directly the presence of magnetic phase separation at a local level. The microscopic magnetic structure of the sample depends on cooling conditions [namely, zero field cooling (ZFC) or field cooling (FC)] and can be continuously controlled through the phase separation range by magnetic field and temperature. The magnetic phase diagrams of the sample have been obtained in a wide ranges of fields and temperatures for both ZFC and FC cases.