Microwave dielectric properties of MgTiO3-based ceramics

Structure and microwave dielectric characteristics of Sr2[Ti1−x(Al0.5Nb0.5)x]O4 (x ≤ 0.50) ceramics

“…It has been reported that the higher degree of covalency (%) leads to have stronger covalent bonds than the ionic bonds among cation and oxygen in oxygen octahera and also the increasing trend in bond strength (s) signifies to have higher stability of crystal structure by the effect of lower vibration restoring force. 13,35,36 These results are in well agreement with not only the higher degree of covalency but also the decreasing trend of dielectric constant for x ≤ 0.50 as discussed above. The rattling effect is strongly dependent on the high bond strength between the cation and oxygen ion in the oxygen octahedron since it generates more rigid octahedra which could decrease the rattling effect and consequently decreases the dielectric constant.…”

“…The bond strength and the degree of covalency (%) between oxygen and B‐Site cation turns stronger with increase in the co‐substitution of Al/Nb at B‐site which consequently decreases τ f . It has been reported that the higher degree of covalency (%) leads to have stronger covalent bonds than the ionic bonds among cation and oxygen in oxygen octahera and also the increasing trend in bond strength ( s ) signifies to have higher stability of crystal structure by the effect of lower vibration restoring force . These results are in well agreement with not only the higher degree of covalency but also the decreasing trend of dielectric constant for x ≤ 0.50 as discussed above.…”

Usage of P–V–L bond theory in studying the structural/property regulation of microwave dielectric ceramics: a review

“…Cubic spinel structures MgO-TiO 2 systems are appealing to the public for their richness in raw materials, low cost and excellent microwave dielectric properties. For instance, three main crystalline phases are reported in the binary MgO-TiO 2 phase diagram: spinel Mg TiO 4 , ilmenite MgTiO 3 and pseudobrookite MgTi 2 O 5 , where Mg 2 TiO 4 and MgTiO 3 exhibit low ε r values and ultra-low dielectric loss (Mg 2 TiO 4 : ST = 1480 °C, ε r = 14.51, Q × f = 161 570 GHz, and τ f = −49.3 ppm per °C; MgTiO 3 : ST = 1400 °C, ε r = 17.75, Q × f = 250 000 GHz, and τ f = −42.5 ppm per °C) 186,187. …”

Microwave Performance, Microstructure, and Crystallization of (Mg0.6Zn0.4)1−yNiyTiO3 Ilmenite Ceramics

“…It was reported that the partial replacement of Mg by B 2+ (B 2+ = Co, Ni, and Zn) increases the structural densification and upgrades the dielectric performance of MgTiO 3 . (Mg 0.95 B 2+ 0.05 )TiO 3 with an ilmenite-type structure has been documented to possess excellent dielectric performance [8,13,14] [22][23][24][25][26][27]. In this paper, with partial substitution of Mg 2+ (0.072 nm) by Ni 2+ (0.069 nm), the microstructure densification of (Mg 0.6 Zn 0.4 ) 0.95 Ni 0.05 TiO 3 was observed, and microwave dielectric performance of that was also further improved compared to (Mg 0.6 Zn 0.4 )TiO 3 .…”