Temperature-Stable and Low-Loss Dielectrics in the Ca(B'^sub 1/2^Ta^sub 1/2^)O^sub 3^ [B'=Lanthanides, Y, and In] System

The ... [B'=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Er, Yb, and In] double perovskite-type ceramics have been prepared by the conventional solid-state ceramic route. The phase purity and surface morphology of the sintered ceramics have been studied by X-ray diffraction (XRD) and scanning electron microscopy methods. XRD study revealed intersubstitution between Ca and B' ions. ... ceramics have relative permittivity (...) in the range 23-30, normalized quality factor (... x f) 20 600-59 200 GHz, and temperature coefficient of resonant frequency (...) -6 to -35 ppm/...C. The dielectric properties of ... ceramics have been tailored by the addition of positive ... materials such as ..., ..., ..., and ..., which form a solid solution or a mixture phase with the parent compound. The 0.7...-0.3... ceramic has ...=27.5, ... x f=41 900 GHz, and ...=-1.2 ppm/...C, and the 0.6...-0.4... ceramic has ...=27.7, ... x f=48 000 GHz, and ...=1.8 ppm/...C. (ProQuest: ... denotes formulae/symbols omitted.)