Studies on annealing and quenching of strontium barium niobate (SBN) single crystals: A-site cation ordering-disordering effect

Abstract

Abstract Quenching and annealing studies have been carried out to investigate the effects of the A-site occupancy in the tungsten bronze structure on the polarization, pyroelectric coefficient, dielectric permittivity, and phase transition (Curie temperature range) behavior of ferroelectric relaxor Sr1−xBa x Nb2O6 (1−x = 0.75, 0.60, 0.50) single crystals. Quenching possibly generates a random distribution of vacancies between A1 and A2 sites and enhances the ordering of the cations in A-site. As a consequence of that, a Tc increase of as much as about 30°C above the Tc of non-quenched state has been observed. Quenching at a higher temperature, i.e., approximately about 1000°C results in reducing the ordering of the A-site because of random distribution of Sr2+, Ba2+, as well as vacancies. A continuous Tc increase accompanied by a decrease in dielectric permittivity and a broadened phase transition is reported and is believed to be due to strain built up because of energetically unfavored distribution of B...