Structural characteristics and microwave dielectric properties of In3+ and Nb5+ co-doped CaTiO3 ceramics

• Published in: Journal of materials science. Materials in electronics Vol. 28; no. 8; pp. 6301 - 6307
• Main Authors: Chen, G. H., Chen, J. S., Kang, X. L., Yang, T., Luo, Y., Yuan, C. L., Zhou, C. R.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-04-2017; Springer Nature B.V
• Subjects: Calcium titanate; Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Dielectric properties; Materials Science; Optical and Electronic Materials; Orthorhombic phase; Permittivity; Perovskite structure; Perovskites; Q factors; Selectivity; Unit cell; Tolerance Factor; Dielectric Constant; Perovskite; Microwave Dielectric Property; Sinter Temperature
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-016-6313-4

CaTi
1−x
(In
0.5
Nb
0.5
)
x
O
3
(0.1 ≤ x ≤ 0.7) ceramics were prepared by a solid-state reaction method. Analysis of XRD data revealed the formation of single orthorhombic phase for all the compositions (0.1 ≤ x ≤ 0.7) and the unit cell volume increases linearly with
x
. SEM results also showed no evidence of secondary phase. The relative permittivity (ε
r
) and temperature coefficient of resonance frequency (τ
f
) decreased and quality factor (Q × ƒ) increased with an increase in
x
from 0.1 to 0.7 except for x = 0.6. The ε
r
decreased with the increase of x, which was depended on the value of α
D
/V
m
and cation “rattling effect”. The change of τ
f
with
x
was related to the variation of the tolerance factor, which influenced the tilting of oxygen octahedral in perovskite structure. Optimum microwave dielectric properties (ε
r
~43.72, Q × ƒ ~12453.48 GHz, τ
ƒ
~3.07 ppm/°C) were achieved at
x
 = 0.65, suitable for use in satellite broadcast systems due to high frequency selectivity.