Enhanced piezoelectric constant and remnant polarisation in K-compensated sodium potassium bismuth titanate

Abstract The influence of volatility of potassium on piezoelectric constant of lead-free 0.8(Na 0.5 Bi 0.5 )TiO 3 –0.2(K 0.5 Bi 0.5 )TiO 3 (NKBT20) is investigated. An excess of 0.8 mol% of K 2 CO 3 compensates the loss of potassium due to volatility. Piezoelectric constant ( d 33 ) of K-compensated NKBT20 is 215 pC/N, which is greater than that have been reported in literature. Splitting of (111) and (200) peaks confirms that the sample is of morphotrophic phase boundary composition with coexistence of rhombohedral and tetragonal phases. Remnant polarisation and coercive field are 56.7 µC/cm 2 and 39 kV/cm respectively. Increase in piezoelectric constant and remnant polarisation is attributed to the fine tuning of rhombohedral and tetragonal phase fractions by optimum compensation of loss of potassium. Present work provides reproducible preparation procedure to enhance piezoelectric and ferroelectric properties.