Microwave dielectric properties of Ba-Nd-Ti-O system doped with metal oxides

Bi2O3/Fe2O3 or Bi2O3/MnO were co-added to 0.15[Ba(1-x)Mx]O-0.25Nd(2)O(3)-0. 6TiO(2) (M = Ca, Sr, and x = 0, 0.05, 0.1, and 0.15) to adjust its high tem perature coefficient of resonant frequency to zero. The specimens were fabr icated by solid state reaction, and their microwave dielectric properties w ere measured by Hakki-Coleman's method. When Ca and Sr of 0.15 were substit uted for Ba, the tau(f) was 85 and 135 ppm/degrees C, respectively. However , as 10 wt.% Bi2O3 and 3 wt.% Fe2O3 were simultaneously added to the system in which Ca and Sr of 0.15 were substituted for Ba, the tau(f) was remarka bly decreased to -5 and 6 ppm/degrees C, respectively. On the other hand, w hen 10 wt.% Bi2O3 and 2 wt.% MnO were simultaneously added to the same syst em, a tau(f) of 8 and 0 ppm/degrees C were obtained, respectively. (C) 2000 Elsevier Science B.V. All rights reserved.