Structural and Dielectric Studies of the Phase Transitions in Pb(Yb1/2Ta1/2)O3-PbTiO3 Ceramics

Abstract

A dielectric phase diagram of the pseudobinary (1 - x)Pb(Yb1/2Ta1/2)O-3-xPbTiO(3) solid solution system was determined: The crystal structures and the dielectric properties were investigated in terms of the PbTiO3 concentration. As the PbTiO3 concentration increases, the crystal structure changes from monoclinic to pseudocubic and then to tetragonal. A morphotropic phase boundary that separates the pseudocubic phase from the tetragonal phase has been determined at x approximate to 0.5. The phase transition of pure Pb(Yb1/2Ta1/2)O-3 is unusual in that it undergoes a paraelectric-antiferroelecrric transition at 310 degreesC and another secondary antiferroelectric-ferroelectric transition at about 177 degreesC. This successive phase transition characteristic confers a rather unique feature on the (1 - X)Pb(Yb1/2Ta1/2)O-3-xPbTiO(3) phase diagram.