Magnetic and Dielectric Proprieties of Multiferroic (1-x)Pb(Fe2/3W1/3)O3-xPbTiO3 Ceramics Prepared Via a Modified Two-stage Solid-state Reaction

Multiferroic Pb(Fe2/3W1/3)O-3-PbTiO3 (PFW-PT) ceramics were synthesized via a modified two-stage solid-state reaction. This method utilized Fe2WO6, prepared at a first-stage, which was subsequently reacted with a stoichiometric amount of PbO and TiO2 at the second stage. This procedure efficiently suppressed the formation of lead tungstates and leads to getting dense ceramics. Electric and dielectric properties of (1-x)Pb(Fe2/3W1/3)O-3-xPbTiO(3) solid solutions were investigated as a function of the frequency and temperature. All samples present density higher than 96% of the theoretical one, low percentage of pyrochlore phase (<2%) and relatively high electrical resistivity (<10(10) Omega.m). RF dielectric measurements over the temperature showed the presence of a peak, which is related to the ferro-paraelectric phase transition and conductive contributions (in the range 200-700K), associated to a electronic hoping mechanism. The dielectric properties of the PFW shows a typical relaxor behaviour for x = 0 and 0.10 with frequency-dependent peak temperature (Tm), while the samples with higher PT-content undergo a 'normal' para-ferroelectric transition at the Curie temperature T-c. The FE phase transition of PFW is shifted to higher temperatures by PbTiO3 (PT) additions and high resistivity are obtained for PT containing samples. Different types of magnetic activity dependent on composition and temperature were found.