Yttrium-modified Bi ₇ Fe 1.5 Co 1.5 Ti ₃ O ₂₁ ceramics with improved room temperature multiferroic properties

Yttrium-modified Bi7Fe1.5Co1.5Ti3O21 Aurivillius phase oxides were synthesized using a modified Pechini method, and their multiferroic properties were investigated as a function of the Y content in the formula Bi7−xYxFe1.5Co1.5Ti3O21. X-ray diffraction investigation suggests the formation of a pure Aurivillius phase when the Y content is less than 1.25, and a Co-doped BiFeO3 impurity appears when the content exceeds 1.25. When the Y content is 1.25, the sample exhibits significantly improved room temperature multiferroic properties with a remanent polarization 2Pr of 11.72 μC cm−2 and a remanent magnetization 2Mr of 3.2 emu g−1. Derivative thermo-magneto-gravimetry measurement indicates that the measured magnetic properties mainly originate intrinsically from the Y-modified Aurivillius phases when the Y content is less than 1.25.