Enhanced ferroelectricity, piezoelectricity, and ferromagnetism in Nd-modified BiFeO3-BaTiO3 lead-free ceramics

Abstract

Lead-free multiferroic ceramics of 0.75Bi1-xNdxFeO3-0.25BaTiO3+1mol. % MnO2 were prepared by a conventional ceramic technique and their structure, piezoelectricity, and multiferroicity were studied. The ceramics sintered at 890-990°C possess a pure perovskite structure. A morphotropic phase boundary of rhombohedral and monoclinic phases is formed at x=0.05. A small amount of Nd improves the ferroelectric and piezoelectric properties of the ceramics. The ferroelectric-paraelectric phase transition becomes gradually diffusive with x increasing. After the addition of Nd, the ferromagnetism of the ceramics is greatly enhanced by ∼320%. The increase in sintering temperature improves significantly the ferroelectric, piezoelectric, and ferromagnetic properties of the ceramics. The ceramics with x=0.05 sintered at 950-990°C possess improved ferroelectricity, piezoelectricity, magnetism and insulation with Pr of 16.5-17.5 μC/cm2, d33 of 113-121 pC/N, Mr of 0.127-0.138emu/g, R of ∼5×109 Ω·cm and high TC of 473-482°C, indicating that the ceramic is a promising candidate for room-temperature multiferroic and high-temperature piezoelectric materials.