Band gap evolution and a piezoelectric-to-electrostrictive crossover in (1 − x)KNbO3–x(Ba0.5Bi0.5)(Nb0.5Zn0.5)O3 ceramics. Issue 8 (6th February 2017) - Pascual-Gonzalez, Cristina
Abstract : A piezoelectric-to-electrostrictive crossover in (1 − x )KNbO3 – x (Ba0.5 Bi0.5 )(Nb0.5 Zn0.5 )O3 . Abstract : The band gap of (1 − x )KNbO3 – x (Ba0.5 Bi0.5 )(Nb0.5 Zn0.5 )O3 (0 ≤ x ≤ 0.25) ceramics narrows slightly from 3.22 eV for x = 0 to 2.89 eV for x = 0.25, in broad agreement with first-principles calculations [ Phys. Rev. B, 2014, 89, 235105]. In addition, an unreported piezoelectric-to-electrostrictive crossover is observed in this compositional range, which is accompanied by a continuous decrease of the maximum electric field-induced strain due to the presence of a non-ferroelectric phase. An electrostriction coefficient of 0.023 m 4 C −2 is measured for x = 0.05, whilst no electromechanical response is observed for non-ferroelectric x = 0.25, even under an applied electric field of 80 kV cm −1 .