Synthesis, structure, and dielectric properties of a new binary antiferroelectric solid solution: (1−x)Pb(Mg_1/2W_1/2)O₃–xPbHfO₃

Dielectric ceramics are one of the most important electrical insulators because of their excellent electrical stability and nonconducting properties. In this work, new complex perovskite solid solutions, (1−x)Pb(Mg_1/2W_1/2)O₃–xPbHfO₃ [(1−x) PMW–xPHf] (0.00 ≤ x ≤ 0.04), were successfully synthesized in the form of ceramics by the solid-state reaction method and sintering process. The X-ray diffraction results indicate that a single perovskite phase with antiferroelectric (AFE) orthorhombic Pmcn symmetry is formed for x < 0.04 which corresponds to the PMW-type solid solution (SS-PMW). For the composition x = 0.04, however, a small amount (about 1%) of ferroelectric orthorhombic C2mm phase that arises from the PHf-type solid solution (SS-PHf) was found to coexist with the Pmcn phase (99%). The dielectric measurements show that the AFE-paraelectric phase transition temperature T_C of the (1−x)PMW–xPHf ceramics increases from 38.2°C (x = 0) to 40.1°C (x = 0.03) with the increasing PHf content, indicating a slightly enhanced AFE ordering degree. The studied materials show a relatively low dielectric constant (~10²), a low dielectric loss (~10⁻²), a high breakdown field strength (~140 kV/cm), and a linear electric field dependence of polarization at room temperature, which make them a new candidate for potential applications as ceramic insulators.