Ferroelectric properties of Li‐doped BaTiO ₃ ceramics

We prepared 3 kinds of Li + ‐doped BaTiO 3 ceramics by the solid‐state reaction method: (i) (Ba 1− x L i x )TiO 3−x/2 having A‐site Li + , (ii) Ba(Ti 1− x L i x )O 3−3x/2 having B‐site Li + , and (iii) x/2 Li 2 CO 3 +BaTiO 3 mixed one, for which we investigated the stable site of Li. The density of all prepared ceramics is above 95%. The results show that the lattice structure, the grain size, and the electric properties of Li + ‐doped BaTiO 3 ceramics are dependent on Li + site. According to the increase in Li content, the cell volume of Ba 1− x L i x TiO 3−x/2 decreases, but that of BaTi 1− x L i x O 3−3x/2 increases. That of x/2Li 2 CO 3 +BaTiO 3 decreases by the small addition of Li, but increases by the large addition of Li. All Li + ‐doped ceramics show antiferroelectric‐like double hysteresis loops. The shape of loops and the dielectric properties are also dependent on the Li site. We suggest that the role of oxygen vacancy accompanied by the Li‐doping is important. By comparison with the results of 3 type ceramics, it is concluded that at x/2Li 2 CO 3 +BaTiO 3 ceramics, the Li + prefers to favorably substitute Ba 2+ at A site for the low concentration of Li but its location was changed to Ti 4+ site for the high concentration of Li.