| Abstract |
A systematic investigation on the dielectric and electronic structure of Mg²⁺/Nb⁵⁺ co−doped rutile−TiO2 ceramics was performed. The (Mg1/3Nb2/3)0.05Ti0.95O2 ceramic was prepared by a solid state reaction method and sintered at 1350 °C for 2 h. Pure rutile−TiO2 phase was detected in the sintered ceramic with highly dense microstructure. By optimizing co−doping concentration, interestingly, the (Mg1/3Nb2/3)0.05Ti0.95O2 ceramic exhibited low loss tangent (< 0.05 at 10³ Hz) and high dielectric permittivity of ≈ 10⁴ with slightly dependent on temperature over a wide range. To understand the cause of high−performance dielectric properties in the (Mg1/3Nb2/3)0.05Ti0.95O2 ceramic, the ground state structure of this material was investigated by the density functional theory. Calculation results revealed that Mg atom is located near the oxygen vacancy. Moreover, our results revealed that the Nb atoms in the (Mg1/3Nb2/3)0.05Ti0.95O2 unlikely form the diamond shape. Hence, it cannot generate large defect−dipole moments. Thus, the colossal permittivity in the (Mg1/3Nb2/3)0.05Ti0.95O2 ceramic should be attributed to the extrinsic effects |
Publication
Journal Publication
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