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 (2P(r)) by about 35% and simultaneously the

Multiferroics; Ferroelectrics; Ferromagnetism

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