94NBT-6BT piezoelektrik tek kristal malzemelerin üretilmesi ve karakterizasyonu

Development of the lead based and lead free piezoelectric single crystals has attracted more attention by various scientists from 1997s to the present due to their perfectly aligned domains. After 2000s, new generation piezoelectric single crystals are more preferred to produce high performance devices due to the rapidly developing electronic technology. However, the use of lead based materials will be prohibited by environmental regulations due to their high volatilization during processing in near future. In recent years, sodium bismuth titanate-barium titanate (94Na0.5Bi0.5TiO3-6BaTiO3) (94NBT-6BT) single crystals considered to be suitable candidate as lead free piezoelectric material because of their strong piezoelectric properties. Recently, considerable research efforts have been devoted to enhance piezoelectric performance of the grown NBT based single crystals. In this thesis, BaTiO3, undoped and Li, Fe, Mn doped 94NBT-6BT single crystals were successfully grown by flux growth technique. Moreover, 94NBT-6BT ceramics and embedded single crystal seed in polycrystalline NBT-BT matrix were sintered by conventional (CS) and spark plasma sintering (SPS) techniques for solid state single crystal growth study. Morphology of the grown crystals and ceramics were characterized by stereo and scanning electron microscopy (SEM). Elemental analysis were performed with energy dispersive X-ray (EDX) and X-ray fluorescence (XRF) methods. Crystalline phase of the single crystals were analyzed by X-ray diffraction (XRD) techniques. Temperature and frequency-dependent dielectric and leakage current properties, and also piezoelectic and ferroelctric properties of the 94NBT-6BT single crystals and ceramics were measured by impedance/gain phase analyzer, LCR meter, d33 meter and AIXACT (aixPES/CMA) piezoelectric and ferroelectric analyzer.