Piezoelectric performances of lead-reduced (1-x)(Bi0.9La0.1)(Ga0.05Fe0.95)O3-x(Pb0.9Ba0.1)TiO3 crystalline solutions in the morphotropic phase boundary

In this investigation, (1-x)(Bi0.9La0.1)(Ga0.05Fe0.95)O-3-x(Pb0.9Ba0.1)TiO3(BLGF-PBT) crystalline solutions have been fabricated by using the solid-state reaction method. A ferroelectric rhombohedral/tetragonal morphotropic phase boundary (MPB) of (1-x)BLGF-xPBT was observed for x=0.4. In the vicinity of MPB, 0.6BLGF-0.4PBT revealed the maximum dielectric constant K and piezoelectric d(33) constant of 1168 and 186 pC/N, respectively. The substitution of 10 at. % Ba for Pb dramatically increased K and d(33) of (1-x)BLGF-xPBT relative to (1-x)BLGF-xPT at the same x content. The Curie temperature T-c of (1-x)BLGF-xPBT was determined to be above 386 degreesC through the compositions investigated. The phase diagram of (1-x)BLGF-xPBT revealed a V-shaped relationship between T-c and x content. The planar coupling coefficient K-p was measured to be 0.37 for 0.6BLGF-0.4PBT, which was stable with increasing the measurement temperature until 170 degreesC. It is demonstrated that BLGF-PBT is a competitive alternative piezoelectric material, with the superior piezoelectricity and lead-reduced composition. (C) 2004 American Institute of Physics.