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

摘要

The phase transition, ferroelectricity, piezoelectricity, and ferromagnetic characteristics of Bi1-x(Ba0.75Ca0.25)(x)Fe1-xTixO3 (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 similar to 43 mu C/cm(2) by dynamic hysteresis mode (DHM); P-r similar to 24 mu C/cm(2) by positive up negative down (PUND) method) is determined in Bi-0.7(Ba0.75Ca0.25)(0.3)Fe0.7Ti0.3O3 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 similar to 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 BiFeO3 ceramics towards applications. (C) 2015 Elsevier B.V. All rights reserved.