Abstract
Lithium, substituting K in the perovskite KTaO3, creates a local electric dipole due to its off-center position with respect to the cubic site. Interaction between these moments leads to a low-temperature phase which is still controversial, since it reveals signatures of both glass-like and long range order behavior. This work covers recent theoretical investigations of the effective Li-Li interaction and the nature of the low-temperature phase in LixKi_xTaO3, performed in the framework of a non-linear shell model. © 1994, Taylor & Francis Group, LLC. All rights reserved.