Effect of Mn and Nb Doped BaTiO3 in the Dielectric Properties in the Ba(Mn1/2Nb1/2)xTi1-xO3

Polycrystalline samples of BaTi1-x (Mn0.5Nb0.5) (x) O-3 with x = 0.025, 0.05, 0.075, 0.1, 0.125, 0.15, and 0.175 have been synthesized by the high-temperature solid-state reaction technique. The effects of cationic substitution of manganese and niobium for titanium at B sites of the BaTiO3 perovskite lattice on symmetry and dielectric properties were investigated. X-ray diffraction at room temperature and dielectric permittivity in the temperature range from 85 K to 500 K and frequency range from 100 Hz to 2 x 10(5) Hz were studied. The evolution from a normal ferroelectric to a relaxor ferroelectric is emphasized. T (C) or T (m) decreases when both manganese and niobium are introduced into the lattice of BaTiO3. High dielectric constant of around 9000 at T (C) = 280 K was found for Ba Ti-0.925(Mn0.5Nb0.5)(0.075)O-3 ceramic. A relaxor ferroelectric with Delta T (m) = 60 K and of about 3500 at 10 kHz with T (m) = 150 K was found for the BaTi0.85(Mn0.5Nb0.5)(0.15)O-3 sample.