PROCESSING AND PROPERTIES OF Na0.5Bi0.5TiO3 PIEZOELECTRIC CERAMICS MODIFIED WITH La, Mn AND Fe

Abstract

Although a great deal of work has been done to understand defect chemistry in "soft" and "hard" PZT-based materials, there is little understanding of how defect chemistry influences the properties of lead-free piezoelectric materials. This paper reports a systematic investigation of doping on the ferroelectric and piezoelectric properties in Na 0.5 Bi 0.5 TiO 3 (NBT)-based ceramics. NBT-based ceramics have been synthesized by traditional solid state routes using several different dopants including lanthanum, manganese, and iron in 1 mol%. The addition of iron and manganese lead to an increase in the coercive field (E c ), a decrease in the piezoelectric coefficient (d33), and an increase in the thermal depoling temperature (T depole ), similar to the behavior of "hard" PZT. Lanthanum, on the other hand, leads to a decrease in the E c , an increase in d33, and a decrease in T depole similar to that seen in "soft" PZT.