Electric field induced monoclinic phase in (Na0.52K0.48)(Nb1-ySby)O3 ceramics close to the rhombohedral-orthorhombic polymorphic phase boundary

The electric field induced structural transformation in (Na0.52K0.48)(Nb(1-y)Sby)O-3 ceramics near the rhombohedral (R)-orthorhombic (O) phase boundary was investigated by means of ex-situ and in-situ synchrotron x-ray diffraction and dielectric measurements. An intermediate monoclinic (M) phase was irreversibly induced from the O phase by poling, leading to a modified polarization rotation path along R-M-O. By comparison, the reversibility of R-M phase transition would cause the phase instability. Both aspects were believed to be responsible for the high piezoelectric activity near the R-O phase boundary. Moreover, enhanced piezoelectric properties were also found to correlate with the thermal stability of the induced M phase. (C) 2013 AIP Publishing LLC.