| Abstrakt: |
Two kinds of solid solution systems of Ta-doped MgTiO3 were identified by X-ray diffraction, which can be represented by the formulae MgTi1− x(Mg1/3Ta2/3) xO3 (0≤ x<0.5) and MgTi1− xTa xO3 (0≤ x<0.05). The conductivity and microwave dielectric loss for the two solid solution systems were examined by AC impedance and microwave resonator measurements, respectively. In the system MgTi1− x(Mg1/3Ta2/3) xO3, the mechanism for the solid solution formation is the isovalent substitution of for Ti4+. In the system MgTi1− xTa xO3, the doping mechanism is the aliovalent substitution of Ta5+ for Ti4+, where for a small amount Ta doping, the oxygen vacancies formed during the high-temperature preparation are filled by an extra oxygen introduced from Ta2O5 and further Ta doping leads to an increase in the contents of and electrons, which was consistent with conductivity measurements. In both systems, the Q× f values improved, e.g., ∼17% for the isovalent substitution at x=0.08 and ∼10% for the aliovalent substitution at x=0.02. The filling oxygen vacancy and the substitution of Ta/Mg for Ti may contribute to the improvement of Q× f values for both systems. [ABSTRACT FROM AUTHOR] |
