Regulation of ferroelectricity in (Na0.5K0.5)1-xAgxNb1-xTaxO3 based on phase boundary and disorder engineering

Abstract

Potassium sodium niobate-based ferroelectric materials are potential alternatives to Pb-based perovskites due to their outstanding ferroelectric and piezoelectric properties. In our previous work, (Na_0.5K_0.5)_1-xAg_xNb_1-xTa_xO₃ was constructed with a coexistence of orthorhombic and tetragonal phases at room temperature, successfully regulating various polarization properties. However, despite the x = 0.075 sample's excellent piezoelectric and ferroelectric characteristics, the significant coercive field it exhibits poses a challenge for polarization. Further investigation is needed to address this issue. This study introduces SrTiO₃ as a second phase into (Na_0.5K_0.5)_0.925Ag_0.075Nb_0.925Ta_0.075O₃, effectively regulating the microstructure and disorder. Moreover, leveraging the synergistic effect of phase boundary and disorder engineering, the ferroelectric properties are well modulated at room temperature. These results provide valuable methods and guidance for regulating ferroelectric properties in lead-free ferroelectrics.