Vibrational spectroscopic and crystal chemical analyses of double perovskite Y ₂ MgTiO ₆ microwave dielectric ceramics

Abstract

Abstract Structure‐property relationships of Y 2 MgTiO 6 , a type of double perovskite materials, were investigated systematically. Rietveld refinement of XRD patterns confirmed that Y 2 MgTiO 6 belongs to the P 2 1 /c space group and has a structure analogous to that of monoclinic Dy 2 MgTiO 6 . In accordance with the observed number of vibrational bands and group theoretical predictions, O and Y ions at the 4e site dominated the Raman peaks. The IR reflectivity spectrum indicated that the major contributions to the relative permittivity and intrinsic loss were modes lower than 500 cm −1 . The measured relative permittivity closely approached the calculated values determined according to P‐V‐L theory, the Clausius‐Mossotti equation and IR fitted results. The larger bond energy for Mg–O bonds than for Ti–O bonds corresponds to a more stable octahedron of [MgO 6 ], as verified by the octahedral distortion. Satisfactory microwave dielectric properties of Y 2 MgTiO 6 ceramics were as follows: ε r = 20.4 ± 0.8, Q × f = 42 060 ± 310 GHz, τ f = −52 ± 3 ppm/°C, sintered at 1450°C.