The Effect of MgO on the Structure and Dielectric Properties of α-BZN Ceramics

The effect of MgO doping (in which Bi3+ or Zn2+ substituted by Mg2+) on the structure and dielectric properties of -BZN ceramics are investigated. X-ray diffraction patterns show that (Bi1.5Zn0.5)(Zn0.5-xMgxNb1.5)O-7 ceramics have an only cubic pyrochlore structure (-BZN), while the secondary phase is found even with the addition of 0.05 mol Mg2+ for (Bi1.5-xMgxZn0.5)(Zn0.5Nb1.5)O-7 ceramics. With the increasing of Mg content, the grain size of (Bi1.5-xMgxZn0.5)(Zn0.5Nb1.5)O-7 increases while the (Bi1.5Zn0.5)(Zn0.5-xMgxNb1.5)O-7 has no obvious change. All the compositions exhibit a typical relaxation behavior with strong frequency dispersion in the low-temperature range. The degree of frequency dispersion can be measured by oT(m) = T-m (1MHz)-T-m (100kHz).