IMF2017

Bismuth ferrite (BiFeO₃; BFO) is one of the most studied multiferroic materials, mainly due to its reported magnetoelectric properties at room temperature, potential use in nonvolatile memory applications and developments in the fundamentals of solid state physics. BFO ferroelectric and antiferromagnetic phase transitions are found significantly above room temperature, i.e., it is a ferroelectric material below T_c ~1100 K, and an antiferromagnetic one below T_N ~650 K. The drawbacks of BFO for bulk practical applications are the low resistivity and the difficult to synthetize single-phased polycrystalline materials. To overcome these problems one solution is the synthesis of solid solutions with other perovskite materials, such as BaTiO₃ or PbTiO₃, and doping these materials with multiple valence ions like Mn. Therefore, in this work, we describe the structural, dielectric, magnetic and Mössbauer spectroscopy studies in 0.9BiFeO₃–0.1BaTiO₃ solid solutions doped with Mn processed by high-energy ball milling. Especially for the Mn doped samples a structurally correlated magnetization enhancement is reported. X-ray diffraction and Rietveld refinement studies revealed a distorted perovskite structure with the coexistence of rhombohedral and monoclinic symmetries. Mössbauer spectroscopy results showed a magnetic spectral signature of ordered Fe³⁺ ions for the rhombohedral phase of the undoped sample, and for both rhombohedral and monoclinic phases of the Mn doped samples. A significant magnetization increase (reaching 0.50 emu/g), associated to the magnetic ordering of the Cm phase and to the retention of the Mn³⁺ valence state, was observed for Mn doped samples.