Dielectric Permittivity Enhancement in PZT by Light Doping with Gd
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0966-T10-04
Dielectric Permittivity Enhancement in PZT by Light Doping with Gd Jorge J. Portelles1, Nelson S. Almodovar1, Juan Fuentes1, Eduardo Martinez2, Oscar Raymond2, Jesus L. Heiras2, and Jesus M. Siqueiros2 1 Facultad de Fisica, Universidad de La Habana, San Lazaro y L, Vedado, La Habana, 10400, Cuba 2 Centro de Ciencias de la Materia Condensada, Universidad Nacional Autonoma de Mexico, Km. 107 Carretera Tijuana-Ensenada, Ensenada, 22860, Mexico
ABSTRACT PbZr0.53Ti0.47O3 doped with 0.6% at. of Gd2O3 has been produced following the traditional solid state reaction technique. The ferro-paraelectric transition temperature is reduced from 386 ∞C to 352 ∞C. Remnant polarization and coercive field measurements were made from the hysteresis loops obtained at 23 ∞C and at different applied electric fields up to a maximum of 17 kV/cm. Piezoelectric performance was studied in the 4 Hz to 4 MHz frequency range at 25 ∞C and the radial electromechanical coupling factor was determined. A detailed electrical conductivity study in the 30-450 ∞C temperature range is performed in a wide frequency interval. The different participating transport mechanisms are elucidated and the corresponding activation energies were determined by fitting the experimental data. In particular, in the 30 to 300 ∞C temperature interval, the ac conductivity follows Jonscher universal relaxation law. INTRODUCTION Lead zirconate-titanate PbZr(1-x)TixO3 (PZT) solid solutions have been widely investigated since the early 1950s due to their remarkable properties from a fundamental standpoint as well as for from the technological point of view [1-4]. Among the relevant characteristics of PbZr0.53Ti0.47O3 (PZT 53/47) are a remarkable piezoelectric effect, a large electro-mechanical coupling factor and a large dielectric permittivity near the tetragonal-rhombohedral morphotropic phase boundary. PZT 53/47 is an interesting material just as it is, however, a lot of work has been dedicated to improve on one particular property of the material and one way to do it is by doping it with different elements that may enter the structure at the A and/or B sites of the ABO3 perovskite structure [1,5,6]. In the last decade, many experiments have been dedicated to the substitution of rare earth ions in the PZT 53/47 structure. Recently, some results have been published on Gd doped PZT obtained by a mechanical alloying (MA) technique and by the solgel method. In all cases, the objective was to determine the influence of the morphology on the dielectric properties of this system [4,7]. In this work, the purpose is to determine the effects of Gd doping on the dielectric, ferroelectric, piezoelectric, and phase transition properties of the PZT 53/47 ceramic prepared by solid state reaction. EXPERIMENT Polycrystalline PZT 53/47 samples doped with 0.6% at. wt. of Gd2O3 were prepared from powders of PbTiO3 (99.9 %, metal basis), PbZrO3 (99.9 %, metal basis), and Gd2O3, (99.9 %, Reacton) all by Alfa Aesar by performing the following steps: First, reactants in stoichiometric a
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