Relationship of Crystal Structure and Microwave Dielectric Properties in Ni 0.5 Ti 0.5 NbO 4 Ceramics with Ta Substitution

• Published in: European journal of inorganic chemistry Vol. 2018; no. 17; pp. 1800 - 1804
• Main Authors: Huang, Xin, Zhang, Huaiwu, Lai, Yuanming, Wang, Gang, Li, Mingming, Hong, Caiyun, Li, Jie
• Format: Journal Article
• Language: English
• Published: 08-05-2018
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.201800016

We have prepared Ni
0.5
Ti
0.5
Nb
1–
x
Ta
x
O
4
microwave dielectric ceramics using a traditional solid‐state reaction method. The influence of Ta
5+
substituted at the Nb
5+
site on the crystal structures and dielectric properties of Ni
0.5
Ti
0.5
Nb
1–
x
Ta
x
O
4
ceramics is discussed. Structural refinement indicates that the distortion in the oxygen octahedron is affected by Ta substitution. The dielectric constant is dependent on the polarization of the NbO
6
octahedron. The
Q
×
f
value is improved as the Ta content increases, because of the increasing packing fractions. The
τ
f
value is mostly dominated by distortions of the Nb–O bonds (
δ
Nb–O
); and
δ
Nb–O
reduces with increasing Ta ion doping in the Nb site, which makes the
τ
f
value decrease with increasing Ta content. Optimal microwave dielectric properties (
ε
r
= 48.5,
Q
×
f
= 17500 GHz, and
τ
f
= 88.6 ppm °C
–1
at the resonant frequency of 6.05 GHz) are obtained for Ni
0.5
Ti
0.5
Nb
1–
x
Ta
x
O
4
ceramics at
x
= 0.2.