The magnetic properties of Bi0.9Ba0.1Fe0.81M0.09Ti0.1O3 solid solutions (M = Co, Mn, Sc, Al)

Solid solutions with general formula Bi0.9Ba0.1Fe0.81M0.09Ti0.1O3 (M = Co, Mn, Sc, Al) together with parental Bi0.9Ba0.1Fe0.9Ti0.1O3 were prepared by the traditional solid state reaction method. Their structural, room temperature magnetic, and dielectric properties were investigated. X-ray diffraction analysis indicated that all samples maintained original R3c space group. M–H hysteresis loop of Co3+ doped sample saturated at an applied field of 1 T with spontaneous magnetization of 1.735 emu/g, while Mn4+ substitution enhanced the magnetization of Bi0.9Ba0.1Fe0.9Ti0.1O3 less strongly; addition of Sc3+ helped decrease magnetic coercive field while Al3+ modified sample exhibited paramagnetic M–H hysteresis loop. Differential scanning calorimetry was applied to determine the Neel temperature (TN) and the TN for undoped, Co3+, Mn4+, Sc3+, Al3+ doped solid solutions were 318.1, 324.3, 335.7, 293.9 and 295.8 respectively. Sc3+ substitution had little influence on the dielectric properties of Bi0.9Ba0.1Fe0.9Ti0.1O3 while Al3+ doping improved its dielectric constant. In contrast, Co3+, Mn4+ doped samples showed decreased permittivity but inhibited tan δ at frequencies larger than 30 kHz.

In Bi0.9Ba0.1Fe0.9Ti0.1O3 solid solution, both magnetic ions (Co3+, Mn3+) and nonmagnetic ions (Sc3+, Al3+) were chosen to partially replace Fe3+. Their magnetic properties were carefully investigated. Figures show M–H loops at RT of Co3+ doped sample (left) and Sc3+ substituted solid solution (right).Figure optionsDownload as PowerPoint slideHighlights
► The electrical resistivity of BiFeO3 is enhanced by forming solid solution with BaTiO3.
► We replace Fe3+ by both magnetic ions Co3+, Mn4+ and nonmagnetic ions Sc3+, Al3+ to investigate the magnetic properties.
► Structure–magnetic property relationship has been established by Rietveld refinement.