Polar State in Li-Doped SrTiO_3

摘要

The effect of Li on the phase state of SrTiO_3 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_5Sr_(1-x)TiO_(3-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 SrTiO_3 lattice. The transition from the thermally activated regime to quantum tunneling is observed at T < 6 K.