Structural, piezoelectric, multiferroic and magnetoelectric properties of (1-x)BiFeO3-xBa1-ySryTiO3 solid solutions

Lead-free (1-x)BiFeO3-xBa1-ySryTiO3 (0 ≤ x ≤ 0.4, 0.0 ≤ y ≤ 0.8) (BF-BST) ceramics were fabricated with the conventional solid-state reaction method. The structural, piezoelectric, multiferroic and magnetoelectric properties have been investigated for these BF-BST solid solutions, especially for the samples near the morphotropic phase boundaries (MPB). Structural analysis shows a coexistence of rhombohedral (R) and tetragonal (T) phases in all the MPB samples, in which the lattice distortion of R and T phases increases overall and decreases, respectively, with increasing y. All the MPB samples show multiferroicity and magnetoelectric effect at room temperature. Both the ferroelectricity and piezoelectricity are found to decrease with increasing y in the MPB samples. It is revealed that high T distortion and low R distortion should contribute dominantly to the high piezoelectricity near MPB in BF-BST solid solutions. These results suggest a possible new strategy for designing high-performance piezoelectric ceramics and also the important role of MPB in the improvement of multiferroicity.