Relaxor Behaviour and Ferroelectric Properties of (Li_0.12Na_0.88)(Nb_0.9-xTa_0.10Sb_x)O₃ Lead-Free Ceramics

New lead-free ceramics (Li_0.12Na_0.88)(Nb_0.9-xTa_0.10Sb_x)O₃ (0.01×0.06) are synthesized by solid-state reaction method. The dielectric, piezoelectric and ferroelectric properties of the ceramics are studied. The dielectric constant dependence with temperature and frequency of the ceramic specimen with x=0.04 shows typical characteristics of relaxor ferroelectrics, and the Vogel--Fulcher relationship is fulfilled. The dielectric behaviour and its relation to the phase transition phenomena are discussed. The polarization hysteresis loops at room temperature are also measured.