| 초록 |
Effect of structural characteristics on microwave dielectric properties of (A1/3B2/3)1-xTixO2 ceramics (A2+=Ni, Mg, Zn; B5+=Nb, Ta) were investigated as a function of Ti4+ content (0.3≤x≤0.7). A single phase with teragonal rutile structure was obtained through the entire composition. Parameters of crystal structure were obtained from the X-ray Rietveld refinement. Dielectric constant(K) of the specimens with Ni2+ was lower than those of Mg2+ and/or Zn2+ due to the simaller ionic polarizability of Ni2+(1.23Å) than Mg2+(1.32Å) and/or Zn2+(2.04Å). For the specimens with A=Ni2+, the quality factor(Qf) of specimens with B=Nb5+ were lower than those of B=Ta5+. These results were attributed to the sinteing temperature and the reduction of Ti4+ ion, which were confirmed by the microstructural analysis. The temperature coefficient of resonant frequencies (TCF) of specimens with B=Nb5+ showed the larger TCF value than those of the specimens with B= Ta5+, because of the change with the degree of the distortion of oxygen octahedral. |
