Microwave dielectric properties of (Zn1/3B2/3)0.5(Ti0.8M0.2)0.5O2 (B = Nb5+, Ta5+, M = Sn4+, Ge4+) ceramics

Dielectric properties of (Zn1/3Nb(2−x)/3Tax/3)0.5(Ti0.8Sn0.1Ge0.1)0.5O2 (x = 0, 1, 2) and/or (Zn1/3Nb1/3Tal/3)0.5(Ti0.8Sn0.2(l−y)Ge0.2y)0.5O2 (y = 0, 0.5, 1) were investigated at the microwave frequencies. For the compositions with single phase of rutile structure, the dielectric constant (K) of specimens was not only dependent on the dielectric polarizabilities, but also on the bond length ratio of apical bond (dapical) to equatorial bond (dequatorial) of oxygen octahedron in the unit cell. Temperature coefficients of the resonant frequencies (TCF) of the specimens with B = Nb5+ and/or M = Sn4+ was larger than those with B = Ta5+ and/or M = Ge4+. These results could be attributed to the changes of the degree of oxygen octahedral distortion. Quality factors (Qf) of the specimens with B = Ta5+ and/or M = Sn4+ were larger than those with B = Nb5+ and/or M = Ge4+.