Effects of the substitution of titanium by iron and niobium on the structure and dielectric properties in BaTi1-x(Fe0.5Nb0.5)xO3 solid solution

Z. Abdelkafi (1) , Najmeddine Abdelmoula (1) , Hamadi Khemakhem (1) , Régnault von Der Mühll (2) , Lahcen Bih (3)

1 LPA - Laboratoire de Physique Appliquée [Université de Sfax]
2 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
3 Laboratoire de Physico-Chimie des Matériaux

Polycrystalline samples of BaTi1−x(Fe0.5Nb0.5)xO3 with x = 0.025, 0.05, 0.075, 0.1, 0.125 and 0.15 have been synthesized by high-temperature solid-state reaction technique. The effects of cationic substitution of iron and niobium for titanium in the B sites for 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 to 500 K with frequencies range from 103 to 2 × 105 Hz, respectively, were studied. The evolution from a normal ferroelectric to a relaxor ferroelectric is emphasized. TC or Tm decreases when both iron and niobium are introduced in the lattice of BaTiO3. A high dielectric constant of around 30,000 at TC = 280 K was found for BaTi0.925(Fe0.5Nb0.5)0.075O3 ceramic. A relaxor ferroelectric with ΔTm = 12 K and ε′r about 13,800 at 10 kHz with Tm = 186 K was found for BaTi0.875(Fe0.5Nb0.5)0.125O3 sample.

Mots clés: Ferroelectrics; X-ray diffraction; Dielectric response

Domaines: Matériaux

Z. Abdelkafi, Najmeddine Abdelmoula, Hamadi Khemakhem, Régnault von Der Mühll, Lahcen Bih. Effects of the substitution of titanium by iron and niobium on the structure and dielectric properties in BaTi1-x(Fe0.5Nb0.5)xO3 solid solution. Journal of Alloys and Compounds, 2007, 427, pp.260-266. ⟨10.1016/j.jallcom.2006.03.028⟩. ⟨hal-00122592⟩