The dynamics of Li+ dipoles distributed in the quantum paraelectric matrix of potassium tantalate is investigated via linear and nonlinear dielectric response. It is found that the highly diluted solid solution K0.995Li0.005TaO3, KLT(005), reveals nearly ideal Debye-type dipolar relaxation with conventional frequency dispersion at intermediate temperatures, 30<T<60 K. At lower temperatures a drastic increase in the linear dielectric susceptibility is measured as predicted by computer simulations Su et al. [J. Appl. Phys. 90, 6345 (2001)]. Being accompanied by a negative divergence of the third-order nonlinear susceptibility, a transition into a chiral glass state as T→Tg≈6 K is conjectured.

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The low temperature behavior of the KTaO 3 type incipient ferroelectric crystals is of constant interest. The quantum fluctuations reduce the transition to the ferroelectric state in these crystals. It is possible that the small amount of the dopant Li + can lead, through the elastic interactions, to local glass-like short-range order or even to the relaxor ferroelectric order for x > 2.6%. We presented that the low lithium doped x = 0.005 KTaO 3 crystals exhibit the dielectric dispersion of ε and ε , suggesting the glass-like behavior in the low temperature range.