Lattice vibrational characteristics and structures-properties relationships of non-stoichiometric Nd[Mg0.5Sn0.5(1+x)]O3 ceramics

Abstract

Non-stoichiometric Nd[Mg 0.5 Sn 0.5(1+x) ]O 3 (-0.04 ≤ x ≤ +0.04)-type samples were prepared using a traditional two-step solid-state sintering process. Their crystal structures, phase compositions, dielectric properties and lattice vibrational characteristics were identified in detail. Double perovskite Nd(Mg 0.5 Sn 0.5)O 3 with a monoclinic structure was distinguished as the main crystalline phase, pure phase was obtained when x < 0, and the sample [Nd(Mg 0.5 Sn 0.49)O 3 ] at x =-0.02 shows the excellent dielectric properties: ε r = 18.74, Q × f = 47,979 GHz. Lattice vibrational characteristics were clarified with Raman and infrared active modes assigned and illuminated, accurately. The intrinsic properties were fitted by four-parameter semi-quantum model, which show that the low-frequency infrared modes yield a more significant contribution to permittivity and dielectric loss. Raman shifts of modes F 2g (A) and F 2g (B) correlate with dielectric constants negatively, which implies that the bond length has a positive correlation with permittivity. Full widths at half maximum of vibritional modes A 1g (O) correlate with dielectric loss values positively and correlate with the degree of order (S) negatively.

The latest process and challenges of microwave dielectric ceramics based on pseudo phase diagrams

“…Nd(Mg 0.5-x Ni x Sn 0.5 )O 3 [487], Nd(Mg 0.5-x Zn x Sn 0.5 )O 3 [488], Nd(Mg 0.5 Sn 0.5-x Ti x )O 3 [489], Nd(Mg 0.5-x Ca x Sn 0.5 )O 3 [490], Nd [(Zn 1-x Co x ) 0.5 Ti 0.5 ]O 3 [491], Nd(Zn 0.5+x Ti 0.5 )O 3 [492], Nd (1+x) (Mg 1/2 Sn 1/2 )O 3 [493], Nd(Mg 0.5 Sn 0.5(1+x) )O 3 [494], La 1-x B x (Mg 0.5 Sn 0.5 )O 3 [495], La (1-x) Sm x (Mg 0.5 Sn 0.5 )O 3 [495], La 0.97 Sm 0.03 (Mg 0.5 Sn 0.5 )O 3 -Ca 0.8 Sr 0.2 TiO 3 [395], La 1-x Yb x (Mg 0.5 Sn 0.5 )O 3 [496], La(Mg 0.5-x Ba x Sn 0.5 )O 3 [497], Pr 0.22 Y 0.78 TiTaO 6 [498], La(Mg 0.4 Sr 0.1 Sn 0.5 )O 3 Nd(Co 0.5 Ti 0.5 )O 3 -Ca 0.8 Sr 0.2 TiO 3 [499,500], La(Mg 0.5-x Sr x Sn 0.5 )O 3 [501], Ca 0.6 La 0.267 TiO 3 -Ca(Sm 0.5 Nb 0.5 )O 3 [502], and La[Al 1-x (Mg 0.5 Ti 0.5 ) x ]O 3 [503] was investigated based on sintering behavior and microstructure. Not only the investigations reported the microwave dielectric properties, but also the structure-property relationship containing intrinsic loss, vibrational modes, and chemical bond characteristics of Y 2 MgTiO 6 was studied in detail, and the schematic representation of vibrational modes of Y site was presented in Fig.…”