Pressure induced magnetic phase separation in La0.75Ca 0.25MnO3 manganite

The pressure dependence of the Curie temperature T C(P) in La 0.75Ca 0.25MnO 3 was determined by neutron diffraction up to 8 GPa, and compared with the metallization temperature T IM(P) (Postorino etal 2003 Phys. Rev. Lett. 91 175501). The behavior of the two temperatures appears similar over the whole pressure range, suggesting a key role of magnetic double-exchange also in the pressure regime where the superexchange interaction is dominant. The coexistence of antiferromagnetic and ferromagnetic peaks at high pressure and low temperature indicates a phase separated regime which is well reproduced with a dynamical mean-field calculation for a simplified model. A new PT phase diagram has been proposed on the basis of the whole set of experimental data.