Multiferroic (ferroelectro-magnetic) properties of bismuth ferrite lead titanate x(BiFeO3)-1-x(PbTiO3)

(BiFeO₃)-(PbTiO₃) is a ferroelectric material, that also demonstrates anti-ferromagnetism with weak ferromagnetism, at room temperature. The morphotropic phase boundary composition, 0.7BiFeO₃ - 0.3PbTiO₃, exhibits a ferroelectric T_C of 635degC and a T_N of 287degC. Presented here is a study of the ferromagnetic transition vs. composition, measured using neutron diffraction and magnetisation from AC susceptibility, as a function of temperature on sintered polycrystalline materials. The antiferromagnetic transition is observed to occur at significantly higher temperatures than previously reported. For 0.7BiFeO₃ - 0.3PbTiO₃ a Neel temperature of 330degC is recorded. Neutron data also indicates that T_N is much less dependant on composition than previously documented.