Yttrium-modified Bi7Fe1.5Co1.5Ti3O21 ceramics with improved room temperature multiferroic properties

Abstract

Yttrium-modified Bi₇Fe_1.5Co_1.5Ti₃O₂₁ 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 Bi_7−xY_xFe_1.5Co_1.5Ti₃O₂₁. 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 2P_r of 11.72 μC cm⁻² and a remanent magnetization 2M_r 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.