Mesoscopic and microscopic phase segregation in manganese perovskites

Mesoscopic (500--2000 \AA{}) and microscopic (5--20 \AA{}) phase segregation with temperature and magnetic field was studied in the model manganite ${\mathrm{Pr}}_{0.7}{\mathrm{Ca}}_{0.3}{\mathrm{MnO}}_{3}$ by high-resolution neutron diffraction and inelastic neutron scattering. Intragranular strain-driven mesoscopic segregation between two insulating phases, one of which is charge ordered (CO), sets in below the CO temperature in zero field. The CO phase orders antiferromagnetically, while the other insulating phase shows spin-glass behavior. After field-induced metallization, the CO phase coexists with a ferromagnetic metallic phase.