Evolution of structure and electrical properties with lanthanum content in [(Bi_(1/2)Na_(1/2))_(0.95)Ba_(0.05)]_(1-x)La_xTiO_3 ceramics

摘要

Lead-free perovskite [(Bi_(1/2)Na_(1/2))_(0.95)Ba_(0.05)]_(1-x)La_xTiO_3 (x=0.00-0.10) ceramics were fabricated via the solid state reaction method and their crystal structures and electrical properties were systematically studied. Transmission electron microscopy examination reveals a transition from a rhombohedral R3c phase with micron-sized complex domains to a mixture of rhombohedral R3c and tetragonal P4bm phases with nanodomains as La content was increased. X-ray diffraction analysis on bulk samples, however, indicates a pseudocubic structure in La-doped compositions. Electrical poling seems to transform the pseudocubic structure to arhombohedral phase in compositions with 0.00