Relationships between crystal structure and microwave dielectric properties of (Zn1/3B2/35+)xTi1-xO2 (B5+ = Nb, Ta) ceramics

Dependence of microwave dielectric properties on the crystal structure of (Zn1/3B2/35+)(x)Ti1-xO2 (B5+ = Nb, Ta) ceramics was investigated as a function of Zn1/3B2/35+O2 (B5+ = Nb, Ta) content (0.4 <= x <= 0.7). Dielectric constant (K) and the temperature coefficient of resonant frequency (TCF) of sintered specimens were strongly dependent on the structural characteristics of oxygen octahedra in rutile structure. Cation rattling and the distortion of oxygen octahedra were dependent on the bond length ratio of apical (d(apical))/equatorial (d(equatorial)) of oxygen octahedra. The quality factor (Qf) was dependent on the reduction of Ti ion as well as the microstructure of the sintered specimens. (C) 2007 Elsevier Ltd and Techna Group S.r.l. All rights reserved.