The crystal structure and electrical properties of CeAlO3 ceramics prepared by the mixed oxide route have been investigated. X-ray and electron diffraction data show the room temperature structure to be described by the tetragonal I4/mcm space group [a=5.3253(5) Å and c =7.5860(9) Å; Z=4, and theoretical density, Dx=6.64 g/cm3]. CeAlO3 ceramics sintered at 1500 °C under flowing 5%H 2-95%N2 gas for 4 h reach ∼94% of Dx with a microstructure of randomly distributed equiaxed grains of average grain size ∼2 μm. Conventional transmission electron microscopy reveals needle-shaped ferroelastic domains in some grains. The relative permittivity εr of CeAlO3 ceramics is ∼18-20 in the range of ∼10-300 K. At room temperature and microwave frequencies, CeAlO3 ceramics exhibit εr∼20.7,Qfr∼40 117 GHz (at 9.5 GHz), and Tf∼ -57 ppm/K. The ion polarizability for Ce3+ is calculated to be 4.46 Å3. Revised dielectric polarizabilities for rare-earth lanthanides are also presented.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)