Modulation on structure and electric properties by tantalum of lead-free NaNbO3 ceramics

Abstract

The variation of structural and electric properties is investigated via different characterization methods for NaNbO3 ceramics modified with Ta5+ ions. At room temperature, substitution of Ta5+ ions can effectively induce the phase coexistence and transition between orthorhombic antiferroelectric P and orthorhombic ferroelectric Q phase in NaNb1-xTaxO3 ceramics. Thus, the ferroelectric and piezoelectric properties could be regulated with the maximum value of d33 (~37.3) at x = 0.05. Besides, with increasing temperature, multiple phase transitions are demonstrated through dielectric, XRD, and in situ Raman results. Moreover, the temperature of various phase transitions gradually shifts toward lower temperature with increasing Ta5+ ions. Correspondingly, the modulation mechanism is also discussed based on the evolution of Raman vibration. This work is instructive for regulatable applications of NaNbO3-based materials.