Abstract
The effect of Li on the phase state of SrTiO3 was studied to clarify the predominant factors of induced polar state in incipient ferroelectrics. Dielectric, ultrasonic and polarization loops measurements were carried out in a temperature range of 3–350 K using ceramic samples of Li x Sr1-x TiO3-x/2 (0 ≤ x ≤ 0.05). The observed relaxor-like features are attributed to a possible polar state arising from off-centre Li+ ions in the perovskite SrTiO3 lattice. The transition from the thermally activated regime to quantum tunneling is observed at T < 6 K.