X-ray diffraction and dielectric properties of Fe3+ substituted Pb(Yb1/2Ta1/2)O3

Abstract

The crystal structure and phase transition of (1-x )Pb(Yb 1/2 Ta 1/2 )O 3 - x Pb(Fe 1/2 Ta 1/2 )O 3 (PYT1-xPFTx) solid solutions for 0≤x≤0.25 have been studied by X-ray diffraction and the dielectric constant measurement. From the analysis of the superlattice structure of the (PYT1-xPFTx) solid solutions, it is found that the crystal structure of PYT1-xPFTx changes from the monoclinic to the pseudocubic as x increases beyond x =0.20 at room temperature. In the composition region (x≤0.20), the dielectric constant vs. temperature curve exhibits a sharp normal paraelectric-antiferroelectric phase transition. For x≥0.05, dielectric dispersion at 177C 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. © 2002 Taylor & Francis.