A series of multiferroic $\left(1-x\right){\text{BiFeO}}_3-x{\text{PbTiO}}_3$ solid solution ceramics were prepared by solid-state reactions. Structural characterization by x-ray diffraction reveals the existence of a morphotropic phase boundary (MPB) region in this system in which a tetragonal, a rhombohedral, and an orthorhombic phase exist simultaneously with a large tetragonality in the tetragonal phase region. The temperature variation of magnetic moment of the samples with MPB compositions, measured under zero-field cooling (ZFC) mode, shows three anomalies arising from the antiferromagnetic orderings of the rhombohedral, tetragonal, and orthorhombic phases, respectively. The significant difference in antiferromagnetic ordering temperatures of the rhombohedral and tetragonal phases is attributed to the different structural effects on the magnetic interactions between the rhombohedral and the tetragonal phases, and the effect of the magnetic dilution on the magnetic ordering strength. The magnetic phase diagram of the $\left(1-x\right){\text{BiFeO}}_3-x{\text{PbTiO}}_3$ solid solution system was established.

• Received 13 December 2007

DOI:https://doi.org/10.1103/PhysRevB.78.014401