Phase transition of Fe and Nb-substitued Pb(Mg1/2W1/2)O-3 ceramics

Abstract

The crystal structure and dielectric properties of (I-x)Pb(Mg1/2W1/2)O-3-xPb(Fe1/2Nb1/2)O-3 (PMW1-xPFNx)(0.0 less than or equal to x less than or equal to 0.26) solid solution have been studied by X-Ray diffraction and dielectric property measurements. On increasing PFN substitutions up to x = 0.14, the crystal structure changes from the cubic to the orthorhombic through a sharp phase transition of the paraelectric (P E)-antiferroelectric (AFE) type that is independent of applied frequency. However, on further increasing PFN substitution (0.16 less than or equal to x less than or equal to 0.26), the dielectric constant curve as a function of temperature becomes gradually broader and the apparent transition becomes frequency-dependent while the low temperature phase crystal structure changes from the orthorhombic to the pseudocubic.