Ferroelectric characteristics in Aurivillius solid solutions:: Bi4-xLnxTi3O12 (Ln = Gd, Dy), 0 < x < 0.8

Using an impedance technique we measured the electrical properties in Bi(4-x)Ln(x)Ti(3)O(12) (Ln = Gd, Dy), with 0 < x < 1. Aurivillius solid solutions. These systems show ferroelectric behavior for small values of x and become relaxor for large values of x (x > 0.2). We present results of the electric susceptibility vs. frequency and also vs. temperature. For the dysprosium solid solution (from x = 0.4 to 0.8. above 550 degreesC) we observed important changes in the activation energy as a function of temperature. The impedance measurements were done from room temperature to 850 degreesC. The solid-solution samples for x values up to 1 were prepared by the solid-solution reaction method. Characterization of the samples by X-ray powder diffraction technique indicate that the single phase has an orthorhombic unit cell. (C) 2001 Elsevier Science B.V. All rights reserved.