Physical properties of the new ceramics in the mixed oxide system Na1−xLixNb1−xSbxO3

New ferroelectric or relaxor ceramics with composition Na1−xLixNb1−xSbxO3 (0.05 ≤ x ≤ 0.30) were elaborated and sintered in the temperature range 1100–1200 °C. The effect of cationic substitution of the sodium with the lithium in the A site and the niobium with the antimony in the B site in the NaNbO3 perovskite lattice on physical properties were investigated. X-ray diffraction at room temperature and dielectric permittivity in the temperature range from 200 to 500 K with frequencies from 0.1 to 200 kHz characterisations were used. X-ray diffraction analysis demonstrates that all samples have a single phase with quadratic perovskite structure. Dielectric measurements show that the material have a classical ferroelectric behaviour for 0 < x ≤ 0.15 and a relaxor one for 0.20 ≤ x ≤ 0.30. The polarisation state was checked by pyroelectric and piezoelectric measurements. For x = 0.20, the piezoelectric coefficient d31 is of 15.3 pC/N.