Structure and microwave dielectric properties of CaSmAlO₄–CaTiO₃–Sm_0.9Nd_0.1AlO₃ ceramics with medium to high permittivity

抄録

The CaSmAlO₄-doped 0.84CaTiO₃–0.16Sm_0.9Nd_0.1AlO₃ ceramics with permittivity around 62 were prepared using a conventional solid-state reaction method. The relationship between their structures and microwave dielectric properties was explored by X-ray diffraction, Raman spectroscopy and scanning electron microscopy. A suitable amount of CaSmAlO₄ addition is beneficial for improving the Q×f value and tuning τ_f concurrently. However, excess amount of CaSmAlO₄ generated secondary phase and deteriorated the Q×f value. The 0.5 mol % CaSmAlO₄-doped 0.84CaTiO₃–0.16Sm_0.9Nd_0.1AlO₃ ceramics exhibited the best performance of ε_r = 62.3, Q×f = 38400 GHz and τ_f = +49.5 ppm/°C sintered at 1400 °C for 6 h. Although the temperature stability needs to be made better, the CaSmAlO₄-doped 0.84CaTiO₃–0.16Sm_0.9Nd_0.1AlO₃ ceramics pave the way to develop a promising candidate for 5G dielectric resonators with medium-high permittivity (60 < ε_r < 70).