Structure characteristics and microwave dielectric properties of novel Re2Ce6O15 (ReY, Sm, Nd, La) ceramics

Based on the cubic fluorite structure, novel ceramic series with Re2Ce6O15 (ReY, Sm, Nd, La) formula had been designed and prepared successfully using solid-state reaction method. The new Re2Ce6O15 (ReY, Sm, Nd, La) ceramics all presented a single phase indexed as CeO2-type structure, belonged to Fm-3m space. The formation mechanism and lattice constant of the crystal structure had been investigated using Rietveld structural refine method. The microstructure of the Re2Ce6O15 (ReY, Sm, Nd, La) ceramics had been evaluated by pores, grain size and its distribution. The dielectric constant had been corrected for the exclusion of pores and depended on the ionic polarizability. The quality factors of the Re2Ce6O15 (ReY, Sm, Nd, La) ceramics had been investigated by packing fraction related to the phonon vibration. The temperature coefficient of resonance frequency had been analyzed using the bond valence theory. The Re2Ce6O15 (ReY, Sm, Nd, La) ceramics exhibited excellent microwave dielectric properties with medium dielectric constant, high quality factors and stable resonant frequency temperature coefficient.