Effects of Co-substitutes on multiferroic properties of Bi5FeTi3O15 ceramics

The samples Bi5FeTi3O15 (BFTO) and Bi5Fe0.5Co0.5Ti3O15 (BFCT) were prepared by incorporating BiFeO3 (BFO) and BiFe0.5Co0.5O3 (BFCO) into the host Bi4Ti3O12 (BTO) using the solid state reaction technique. The Raman shift data indicate that the as-prepared materials are of the four-layer Aurivillius phase with an orthorhombic symmetry. At room temperature (RT) and under a driving electric field of 230 kV/cm, the half substitution of Fe by Co ions is found to result in the increase in the remanent polarization (2Pr)(2Pr) by about 35% and simultaneously the decrease in 2Ec2Ec by about 41%, respectively. The magnetic moment at least tripled its value by substituting half Fe ions by Co ions. The 2Mr2Mr of BFCT is about three thousand times the value of BFTO.

► The origin of the improved ferroelectricity of BFCT was investigated.
► Raman scattering was used to study the effect of Co doping on the structure of BFCT.
► It is found that Raman peak variation corresponds to the magnetic phase transition.