Large switchable polarization and piezoelectricity in multiferroic BiFeO3-Bi0.5K0.5TiO3-based single crystals

We report the structural, ferroelectric (FE), piezoelectric, and converse magnetoelectric (ME) effects in a series of Cr/Mn doped BiFeO3-Bi0.5K0.5TiO3-based (BF-BKT) single crystals. The Cr and Mn co-doped BF-BKT crystal (i.e., CrMn04) shows a large switchable polarization of 12ΔP ∼ 59.4 μC/cm2 and large-signal piezoelectric coefficient d33* at room temperature, and nearly thermally stable piezoelectric coefficient of d33 ∼ 212 pC/N below depolarization temperature Td ∼ 358.7 °C. A high DC resistivity of ρ > ∼1.0 × 105 Ω cm for T < ∼346.5 °C was also observed in CrMn04 crystal. All samples exhibit coexistent antiferromagnetic and FE orders and evident electric control of magnetism. The simultaneous existence of good performance of ferroelectricity, piezoelectricity, and converse ME effects in especially the CrMn04 crystal suggests its potential application in multi-functional devices.