The Effect of Dopants on the Dielectric Properties of Ba(B’1/2Ta1/2)O3 (B’=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Yb, and In) Microwave Ceramics

Datum

Lamrat Abdul Khalam, Prabhakaran Sreekumari Anjana, Mailadil Thomas
Sebastian
Published Online: Nov 5 2008 3:07PM

DOI: 10.1111/j.1744-7402.2008.02307.x

ABSTRACT
Low-loss dielectric ceramics based on Ba(B’_1/2Ta_1/2)O₃
(B’=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, Yb, and In) complex
perovskites have been prepared by the solid-state ceramic route. The
dielectric properties (ɛ_r, Q_u,
and τ_f) of the ceramics have been measured in
the frequency range 4–6 GHz by the resonance method. The resonators have
a relatively high dielectric constant and high quality factor. Most of
the compounds have a low coefficient of temperature variation of the
resonant frequencies. The microwave dielectric properties have been
improved by the addition of dopants and by solid solution formation. The
solid solution Ba[(Y_1−xPr_x)_1/2Ta_1/2]O₃
has x=0.15, with ɛ_r=33.2,
Q_u×f=51,500 GHz,
and τ_f≈0. The microwave dielectric properties
of Ba(B’_1/2Ta_1/2)O₃
ceramics are found to depend on the tolerance factor (t),
ionic radius, and ionization energy.

Online Access to Journal of Applied Ceramic Technology