Crystal Structure and Microwave Dielectric Properties of LaLuO ₃ Ceramics

Dense LaLuO 3 ceramics were prepared by the conventional solid‐state reaction route. Their room‐temperature (RT) crystal structure and microwave (MW) dielectric properties were investigated. Rietveld refinements performed on X‐ray diffraction data show the RT crystal symmetry to be best described by the centrosymmetric orthorhombic Pnma space group [ a =6.01888 (9) Å, b =8.37489 (12) Å, and c =5.81841 (8) Å, Z =4]. This space group assignment was further corroborated by Raman spectroscopy analysis. At RT and MW frequencies, LaLuO 3 ceramics sintered at 1525°C/4 h exhibit a relative permittivity, ɛ r =22.4, a quality factor, Q u × f =14 400 GHz (at 5.14 GHz), and temperature coefficient of resonant frequency, τ f =−7.5 ppm/°C. ɛ r corrected for porosity was calculated as 23.9.