Magnetic And Dielectric Proprieties Of Multiferroic (1-x)pb(fe 2/3w 1/3)o 3-xpbtio 3 Ceramics Prepared Via A Modified Two-stage Solid-state Reaction

摘要

Multiferroic Pb(Fe 2/3W 1/3)O 3-PbTiO 3 (PFW-PT) ceramics were synthesized via a modified two-stage solid-state reaction. This method utilized Fe 2WO 6, prepared at a first-stage, which was subsequently reacted with a stoichiometric amount of PbO and TiO 2 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(Fe 2/3W 1/3)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 Ω.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 200-700 K), 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 PbTiO 3 (PT) additions and high resistivity are obtained for PT containing samples. Different types of magnetic activity dependent on composition and temperature were found.