X-Ray Diffraction and Dielectric Properties of Fe 3+ Substituted Pb(Yb 1/2 Ta 1/2 )O 3

Abstract

The crystal structure and phase transition of (1 m x )Pb(Yb 1/2 Ta 1/2 )O 3 - x Pb(Fe 1/2 Ta 1/2 )O 3 (PYT 1 m x PFT x ) solid solutions for 0 h x h 0.25 have been studied by X-ray diffraction and the dielectric constant measurement. From the analysis of the superlattice structure of the (PYT 1 m x PFT x ) solid solutions, it is found that the crystal structure of PYT 1 m x PFT x changes from the monoclinic to the pseudocubic as x increases beyond x =0.20 at room temperature. In the composition region ( x h 0.20), the dielectric constant vs. temperature curve exhibits a sharp normal paraelectric-antiferroelectric phase transition. For x S 0.05, dielectric dispersion at 177°C which is the secondary phase transition point of PYT disappears. Beyond x =0.20, the dielectric constant vs. temperature curve shows significant broadening, but no relaxor behavior has been detected.