Magnesium fluoride doped MgTiO3 ceramics with ultra-high Q value at microwave frequencies

Optical and structural properties of Mn-doped magnesium titanates fabricated with excess MgO

“…It has been shown [5,25] that adding of excess MgO as low as 2 mol. % accelerates MgTiO 3 formation and inhibits formation of the MgTi 2 O 5 in accordance with the reaction:…”

“…For decades the interest to magnesium metatitanate, MgTiO 3 , was motivated by its application in low loss microwave dielectric resonators as a material with high dielectric constant (ε r ~17) and high-quality factor (Q f ~160,000 GHz) [1,2]. To improve the performance of MgTiO 3 -based microwave dielectric ceramics the effect of doping with metal ions like Ni, Zn, Co, Mn and others on microstructure and dielectric properties of MgTiO 3 has been studied [3][4][5]. In particular, the doping with Mn 4+ and W 6+ was shown to be efficient in producing MgTiO 3 ceramics of high insulation resistance when sintering is carried out in reducing atmosphere [6].…”

“…The effect of Mg-doping on crystal phase formation and dielectric characteristics of MgTiO 3 ceramics was also investigated [5,24]. In particular, a dramatic enhancement of Q f value up to 262,900 GHz was demonstrated in 3 wt% MgF 2 -doped MgTiO 3 ceramic sintered at 1300 • C [5].…”

“…The effect of Mg-doping on crystal phase formation and dielectric characteristics of MgTiO 3 ceramics was also investigated [5,24]. In particular, a dramatic enhancement of Q f value up to 262,900 GHz was demonstrated in 3 wt% MgF 2 -doped MgTiO 3 ceramic sintered at 1300 • C [5]. This effect was explained by the influence of MgF 2 on crystal phase formation (the Mg-rich compound inhibited the formation of MgTi 2 O 5 and promoted the formation of Mg 2 TiO 4 ), the production of the liquid phase, which optimizes the pore structure of ceramics and improves the sintering process, as well as the decrease of the leakage current owing to the grain boundary barrier effect.…”

The Structure and Microwave Dielectric Properties of MgTi1−x(Mn1/3Nb2/3)xO3 Ceramics

“…τf is an essential consideration in the practicality of microwave dielectric ceramics, which represents the temperature stability of microwave components in the operating environment. According to Equation ( 11), the variation in τf is closely related to the dielectric constant temperature coefficient (τε), and Equation ( 12) is the expression for τε obtained There have been numerous studies that have delved into the factors influencing microwave dielectric properties [24][25][26][27]. In general, Qf is mainly affected by both intrinsic and non-intrinsic factors.…”