Electric field induced phase instability in typical (Na,K)(Nb,Sb)O3-LiTaO3 ceramics near orthorhombic and tetragonal phase boundary

The Li, Ta, and Sb modified (Na,K)NbO3 ceramics were reported to exhibit excellent piezoelectric properties typically in the vicinity of orthorhombic (O) and tetragonal (T) phase boundaries. Ex-and in-situ synchrotron x-ray diffraction measurements have provided a direct evidence of the electric-field induced phase instability owing to reversible phase transition between monoclinic (M-c) phase and T phase. A low-symmetry Mc phase was irreversibly produced from the initial O phase after the electric field was applied. Experimental results suggested that the M-c-T phase coexistence and reversible M-c-T phase transition (phase instability) may be responsible for enhanced piezoelectric activity in these compositions. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4748320]