Polycrystalline samples of Pb4.95Ba0.05Ge3-xSixO11 (x = 0.3, 0.6, 1.00
) have been prepared by high-temperature solid-state-reaction techniqu
e. X-ray powder diffraction method has been used to check the formatio
n of the compounds. Studies of dielectric permittivity and loss have b
een carried out both as a function of frequency (10(2) to 10(4) Hz) an
d temperature (-180 to 200 degrees C) for different concentrations of
silicon as dopant. It has been observed that the ferroelectric phase t
ransition temperature T-c decreases with the increase of silicon conce
ntration.