Phase transition, piezoelectric, and multiferroic properties of La(Co_(0.5)Mn_(0.5))O_3-modified BiFeO_3-BaTiO_3 lead-free ceramics

摘要

(0.75-x)BiFeO_3-0.25BaTiO_3-xLa(Co_(0.5)Mn_(0.5)O_3+1 mol% MnO_2 lead-free ceramics (x = 0-0.10) were synthesized by a conventional solid-state reaction route and the effects of (Co_(0.5)Mn_(0.5)O_3 on phase transition, piezoelectric, ferroelectric, and multiferroic properties of the ceramics were investigated. The ceramics can be well sintered at 960 ℃ for 2 h. After the addition of (Co_(0.5)Mn_(0.5)O_3, the crystal structure of the ceramics is transformed from rhombohedral (space group R3c) to orthorhombic symmetry (space group Amm2), and the morphotropic phase boundary (MPB) of rhombohedral and orthorhombic phases is formed at x = 0.01-0.03. The dielectric peak of the ceramics was found to become diffusive with increasing x. The ceramics with x = 0-0.03 possess strong piezoelectricity with d_(33) of 95-108pCN~(-1) strong ferroelec-tricity with P_r of 2.2-18.1 μC cm~(-2), considerable magneto-electric coefficient of 372-672 mV/cm Oe, and high Curie temperature of 523-659 ℃, showing potential applications in multiferroic devices.