Enhanced ferroelectricity, piezoelectricity and ferromagnetism in (Ba0.75Ca0.25)TiO3 modified BiFeO3 multiferroic ceramics.

The phase transition, ferroelectricity, piezoelectricity, and ferromagnetic characteristics of Bi 1− x (Ba 0.75 Ca 0.25 ) x Fe 1− x Ti x O 3 ( x = 0.2–0.4) ceramics have been systematic studied. The rhombohedral R3c and tetragonal P4mm phases are determined for x = 0.2 and x = 0.4, respectively, and the composition of x = 0.3 indicates the rhombohedral and tetragonal diphase structure. The saturated P – E loop with a significantly enhanced remnant polarization ( P r ∼43 μC/cm 2 by dynamic hysteresis mode (DHM); P r ∼24 μC/cm 2 by positive up negative down (PUND) method) is determined in Bi 0.7 (Ba 0.75 Ca 0.25 ) 0.3 Fe 0.7 Ti 0.3 O 3 ceramics at room temperature. The coercive field is greatly suppressed with increasing x . The enhanced remnant magnetization (0.07 emu/g at 300 K) is also achieved in the optimal composition x = 0.3. The room temperature strain–electric field (s–E) curves indicates a large strain ∼0.2% in the composition of x = 0.3. The comprehensive enhancement of ferroelectricity, piezoelectricity, and magnetization in composition of x = 0.3 suggests that introducing phase boundary is a promoting way to put BiFeO 3 ceramics towards applications. [ABSTRACT FROM AUTHOR]