Eur. Phys. J. B 18, 605-610 (2000)
https://doi.org/10.1007/s100510070008

Relaxor-like and spectroscopic properties of niobium modified barium titanate

¹ Laboratoire de Physique de la Matière Condensée, Université de Picardie Jules Verne, 33 rue Saint-Leu, 80039 Amiens, France
² Institut de Chimie de la Matière Condensée de Bordeaux, CNRS, 87 avenue du Dr. A. Schweitzer, 33608 Pessac, France

Corresponding author: ^a robert.farhi@sc.u-picardie.fr

Received: 12 July 2000
Published online: 15 December 2000

Abstract

Dielectric susceptibility measurements on niobium-modified barium titanate ceramics for Nb compositions extending up to the solubility limit (18% ) show that these materials display relaxor-like properties for compositions larger than Nb. Raman spectra exhibit extra modes attributed to local responses related with the substitution of niobium for titanium ions. The behaviour of this barium titanate modification, in which Nb⁵⁺ aliovalent cations are substituted for Ti⁴⁺, is discussed by comparison with the zirconium-modified series, in which, oppositely, only a size difference characterizes the substitution on the B site. It is emphasized that electrical random fields created in the former case are more efficient in inducing a relaxor behaviour than elastic random fields created in the latter. The nature of the complex defects expected from the inherent high concentration of barium vacancies is discussed in connection with photoluminescence spectra.