Microwave dielectric properties of (A2+ 1/3B5+ 2/3)0.5Ti0.5O2 (A2+ = Zn, Mg, B5+ = Nb, Ta) ceramics

Dielectric properties of (A
²⁺

_1/3
B
⁵⁺

_2/3
)
_0.5
Ti
_0.5
O
₂
(A
²⁺
= Zn, Mg, B
⁵⁺
= Nb, Ta) (A
²⁺
= Zn, Mg, B
⁵⁺
= Nb, Ta) ceramics were investigated at microwave frequencies. A single phase with tetragonal rutile structure was obtained through the entire compositions. Dielectric properties were strongly dependent on the structural characteristics. The specimens with B
⁵⁺
= Nb showed a larger dielectric constant than those with B
⁵⁺
= Ta due to the decrease of bond valence. Quality factors (Qf) of the specimens with B
⁵⁺
= Ta were larger than those with B
⁵⁺
= Nb. Temperature coefficient of the resonant frequencies (TCF) of (Zn
_1/3
Nb
_2/3
)
_0.5
Ti
_0.5
O
₂
was larger than that of (Mg
_1/3
Ta
_2/3
)
_0.5
Ti
_0.5
O
₂
. These results could be attributed to the changes of the temperature coefficient of dielectric constant and the degree of oxygen octahedral distortion.