New lead-free relaxors based on the K_0.5Na_0.5NbO₃–SrTiO₃ solid solution

New lead-free relaxors have been produced from the K_0.5Na_0.5NbO₃–SrTiO₃ (KNN-STO) system. The solid solubility within the studied range of compositions (1 - x) K_0.5Na_0.5NbO₃–xSrTiO₃ was observed for x up to 0.33. A pseudo-cubic perovskite structure was determined for x = 0.15 to 0.25. The high density and the uniform distribution of fine grains and pores were confirmed by the translucency of these ceramics. The 0.85KNN-0.15STO composition reaches the dielectric permittivity of above 3000 at room temperature. Dielectric spectroscopy measurements revealed that, as with lead-based complex perovskites, the cationic distribution disorder is reflected in relaxorlike properties, thus suggesting possible applications based on this environmentally friendly lead-free ceramic system.