Improved ferroelectric and pyroelectric properties of Pb-doped SrBi_4Ti_4O_(15) ceramics for high temperature applications

摘要

Ferroelectric properties of Pb-modified strontium bismuth titanate ceramics with chemical formula Sr_(1-x)Pb_xBi_4Ti_4O_(15) (x = 0-0.4) were investigated. Polycrystalline ceramics were synthesized by soft chemical method to study the effect of Pb-doping on its physical properties. X-ray diffraction analysis revealed a bismuth layered structure for all the compounds. The doping resulted in an increased tetragonal strain and improved ferroelectric properties. Scanning electron microscope images showed plate like grain morphology with random orientation of platelets. The ferroelectric transition temperature of the ceramics increased systematically from 525 °C to 560 °C with the increase of doping concentration. The piezoelectric coefficient (d_(33)) of the ceramics was enhanced significantly with Pb doping, exhibiting a maximum value of 21.8 pC/N for 40mol.% Pb-doped SBT. Pyroelectric studies carried out using the Byer-Roundy method indicated that the modified SBT ceramics are promising candidates for high temperature pyroelectric applications.