Structural and relaxor behavior of BaZr_xTi_(1-x-y) (Zn_(1/3)Nb_(2/3))_yO_3 ceramics obtained by a solid-state reaction

摘要

BaZr_xTi_(1-x-y)(Zn_(1/3)Nb_(2/3)) _yO_3 (BZT-ZN) ceramics (x = 0.1) were prepared by the solid-state reaction route and their structural and dielectric properties were investigated. It was found at room temperature that the ceramics with y = 0,0.05 and 0.1 present perovskite-type cubic structure. The temperature and frequency dependence of the dielectric constant was investigated in the temperature range from 80 to 400 K and for frequencies ranging from 0.1 to 500 kHz. It was observed that when y increases from 0 to 0.1, the transition temperature decreases and the degree of diffuseness of the phase transition increases. For y = 0.1, a clear relaxor behavior was noted. In this case, the dielectric relaxation rate followed de Vogel-Fulcher relation with an activation energy of E_a = 0.1 eV, an attempt frequency F_0 = 2 × 10 ~(14) Hz and a static freezing temperature T_(VF) = 122 K. The results are discussed in terms of existing models.