Nano/micro Sr2Bi4Ti5O18 crystallites: Size dependent structural, second harmonic and piezoelectric properties

Abstract

Strontium bismuth titanate (Sr2Bi4Ti5O18) powders comprising crystallites of average sizes in the range of 94–1400nm were prepared via citrate-assisted sol-gel route. With an increase in the average crystallite size there was a change in the lattice parameters and shift in the Raman vibration modes. Second harmonic signal (532nm) intensity of the Sr2Bi4Ti5O18 powders increased with the increase in the average crystallite size and the maximum intensity obtained in the reflection mode was 1.4 times as high as that of the powdered KH2PO4. Piezo Force Microscopic analyses carried out on isolated crystallite of size 74nm, established a single domain nature with the coercive field as high as 347kV/cm. There was a systematic increase in the d33 value with an increase in the size of the isolated crystallites and a high piezoelectric coefficient of ∼27pm/V was obtained from an isolated crystallite of size 480nm.