Effect of CeO2 and ZrO2 doping on the dielectric characteristics of CCTO ceramics

CaCu
3
Ti
4
O
12
(CCTO) ceramics doped with Ce
⁴⁺
and Zr
⁴⁺
were synthesized by conventional solid state reaction to investigate the effect of multi-doping on giant permittivity and dielectric properties. The phase compositions and dielectric properties of CaCu
3
Ti
4
O
12
, Ca
1−x
Ce
x
Cu
3
Ti
4
O
12
and Ca
1−x
Ce
x
Cu
3
Ti
3.95
Zr
0.05
O
12
(x=0.5%, 1%, 2%) ceramics were studied by X-ray diffraction (XRD) and impedance spectroscopy etc‥ It was found that through co-doping, the dielectric loss can be reduced while maintaining high dielectric constant. The relaxation behaviors of grain and grain boundaries were fitted via impedance plots. It is shown that the decrease of tanδ is mainly due to the increase of resistance of grain boundaries.