Incommensurate phases in ferroelectric tetragonal tungsten bronzes

Abstract

Abstract Using X-ray scattering, incommensurate phases have been disclosed in some well known ferroelectric tetragonal tungsten bronzes. The results are compared to those recently obtained for Barium Sodium Niobate. It is shown that the existence of incommensurate phases is probably a basic feature for this structural family, which is provoked by a collective shearing of the oxygen octahedra in the structure