Crystal structures and high microwave dielectric properties in Li+/Ti4+ ions co-doped Li3Mg2NbO6 ceramics

Abstract

A series of novel Li3+xMg2Nb1-xTixO6 (0.02 ≤ x ≤ 0.08) ceramics with excellent microwave dielectric properties and relatively low sintering temperatures were synthesized via the solid-phase method. The correlations between sintering characteristics and microwave dielectric properties of the novel system were analyzed in detail. By (Li+/Ti4+) ions co-doped Li3Mg2NbO6 ceramics, all compounds possessed a single phase with orthorhombic structure, pertaining to the space group Fddd (70). The change regulation of dielectric constant and Q*f values was similar to density, which ascended to the maximum value first and then declined as the sintering temperature increased. Furthermore, the τf values constantly shifted to 0 ppm/°C with the content of complex ions (Li+/Ti4+) increasing. The best properties of Li3.06Mg2Nb0.94Ti0.06O6 ceramics sintered at 1025 °C were εr = 14.34, Q*f = 154,113 GHz, and τf = −2.17 ppm/°C.