DIELECTRIC PROPERTIES OF Sr-DOPED Na_(0.5)Bi_(0.5)TiO_3-Ba_(1-x)Sr_xTi_(0.995)Zr_(0.005)O_3 CERAMICS SYNTHESIZED BY WET SOLID-STATE METHOD

摘要

New dielectric composite ceramics Na_(0.5)Bi_(0.5)TiO_3-Ba_(1-x)Sr_xTi_(0.995)Zr_(0.005)O_3(NBT-BSTZ) (x=0.05, 0.1, 0.2, 0.3) have been fabricated by the wet solid-state route. The effect of Sr content on phase structure and electrical properties has been studied in detail. The X-ray diffraction analysis illustrates that the composites consist of tetragonal perovskite. With increasing Sr content, the ceramic capacitors display larger dielectric constant, better temperature stability, and lower dielectric loss in dielectric behavior. The ceramics with composition x = 0.3 possess a large dielectric constant (ε_r) of 2522. The temperature coefficient of capacitance of NBT-BSTZ varies from -39% to 36% in the temperature range between 0 and 200 °C. The dielectric loss of capacitance is below 0.07 while the Sr content is 0.3 in the whole range of measured temperatures. The results indicate that Sr-doping is an effective method to modulate the temperature stability and dielectric loss of the NBT- BSTZ dielectric ceramics.