New dielectric material systems of SrxNd2(1–x)/3TiO3 perovskites-like at microwave frequencies

摘要: Abstract Perovskite compounds, Sr x Nd 2(1− )/3 TiO 3 (SNT ) with ranging from 0.05 to 0.2, were prepared by the conventional solid–state reaction method. X-ray diffraction patterns illustrated that high density and single phase products obtained for all samples, indicating a small level of addition could substantially stabilise structure maintain 2/3 ceramics. But there was also an orthorhombic space groups transition Pnma P4/mmm when above 0.18. In addition, dielectric constant ( e r SNT ceramics had improved ∼85.6 ∼112 increasing value due larger ionic polarizability 2+ than 3+ . Notably, product Q resonant frequency  ×  f ∼295–650 at 3.07–3.32 GHz strongly dependent on grain size cation deficient in present systems. Either or decreasing A-site vacancies led increase value. Besides, temperature coefficient τ sintered at their optimum densification gradually increases 191.7 ppm/°C  = 0.05) 221.3 ppm/°C  = 0.2), which results lower rattling effect higher symmetry BO 6 octahedra perovskite according bond valence theory tolerance factor t ).