The Structure and Microwave Dielectric Properties of MgTi<sub<1−<i<x</i<</sub<(Mn<sub<1/3</sub<Nb<sub<2/3</sub<)<i<<sub<x</sub<</i<O<sub<3</sub< Ceramics

MgTi<sub<1−<i<x</i<</sub<(Mn<sub<1/3</sub<Nb<sub<2/3</sub<)<i<<sub<x</sub<</i<O<sub<3</sub< (<i<x</i< = 0–0.30) ceramics were prepared via the solid-state reaction method. The phase composition, microstru...
Ausführliche Beschreibung

MgTi<sub<1−<i<x</i<</sub<(Mn<sub<1/3</sub<Nb<sub<2/3</sub<)<i<<sub<x</sub<</i<O<sub<3</sub< (<i<x</i< = 0–0.30) ceramics were prepared via the solid-state reaction method. The phase composition, microstructure, bond characteristics, and microwave dielectric properties of MgTi<sub<1−<i<x</i<</sub<(Mn<sub<1/3</sub<Nb<sub<2/3</sub<)<i<<sub<x</sub<</i<O<sub<3</sub< (<i<x</i< = 0–0.30) were systematically investigated. The MgTi<sub<1−<i<x</i<</sub<(Mn<sub<1/3</sub<Nb<sub<2/3</sub<)<i<<sub<x</sub<</i<O<sub<3</sub< ceramics presented an ilmenite type with an <i<R</i<-3 space group, and the secondary-phase MgTi<sub<2</sub<O<sub<5</sub< only existed at <i<x</i< = 0 and 0.30. The introduction of (Mn<sub<1/3</sub<Nb<sub<2/3</sub<)<sup<4+</sup< effectively suppressed the formation of the MgTi<sub<2</sub<O<sub<5</sub< phase. The variation trend of the dielectric constant (<i<ε<sub<r</sub<</i<) was the same as relative density. The quality factor (<i<Qf</i<) value was enhanced by the stable microstructure, which was caused via the lattice energy of Ti/(Mn<sub<1/3</sub<Nb<sub<2/3</sub<)-O bonds. And a high <i<Qf</i< value (353,000 GHz) was obtained for MgTi<sub<1−<i<x</i<</sub<(Mn<sub<1/3</sub<Nb<sub<2/3</sub<)<i<<sub<x</sub<</i<O<sub<3</sub< (<i<x</i< = 0.04) ceramics sintered at 1250 °C. In addition, the introduction of Mn<sup<2+</sup< ions with a larger ionic radius exacerbates the distortion of TiO<sub<6</sub< octahedra, leading to significant fluctuations in the temperature coefficient of the resonance frequency (<i<τ<sub<f</sub<</i<) value. Ausführliche Beschreibung