THE STRUCTURE AND DIELECTRIC PROPERTIES OF NEW OXYFLUORIDES

摘要

The structure of solid solution Bi_(1.5)(Zn_(1-x)Li_x)Nb_(1.5)(O_(7-x)F_x) obtained by substitution of oxygen by fluorine in the oxide Bi _(1.5)ZnNb_(1.5)O_7 is cubic pyrochlore for 0≤x≤0.15. For 0.80≤x≤1.00, a distorted modification with low symmetry results, while the mixed phases of the above two are formed for other values of x between 0.15 and 0.80. The temperature dependences of the dielectric constants have been studied, and a dielectric anomaly at low temperatures (less than -100℃) has been observed.