Structural stability, phase transition and dielectric properties of Pb(Mg1/2W1/2)1−xMxO3 (M = Zr,Sn, Ti) ceramics.

Pb(Mg1/2W1/2)1−xMxO3 (M = Zr,Sn,Ti) ceramics have been prepared by the conventional ceramic process. Their crystallographic, phase transition and dielectric properties have been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and impedance analyzer in this paper. The solubility of the tetra-valent cation in Pb(Mg1/2W1/2)1−xMxO3 decreases in the sequence of Ti4+ > Zr4+ > Sn4+. The doping led to the phase transition from orthorhombic antiferroelectric to cubic paraelectric phase, the microscopic nature of which could be attributed to the contraction of Pb-O12 dodecahedron. A definition of the ordering parameter of the cubic phase was deduced to quantitatively evaluate the B-site ordering degree which decreased with the increase in doping concentration. Anti-site disordering of Mg2+ and W6+ occurred in the high-level doping compositions, which led to the relaxor behavior observed in Ti4+-doped series with x = 0.01 composition. Both of the maximum dielectric permittivity and loss in the paraelectric phase increased with the increasing doping concentration. [ABSTRACT FROM AUTHOR]