Manifestation of polaronic states in ferroelectric relaxor PMN

Small polaron states in the model ferroelectric relaxor PMN were confirmed in this work by detection of the characteristic IR-absorption accompanied by light-induced polaron transport. The mechanism of an influence of mobile polaronic clusters on the polar cluster reorientations and, as a result, on the co-operative phenomena in relaxor is developed. Here mobile polaronic clusters can move on the interfaces of polar clusters with carrying of their polarizations. The latter are moving self-consistently with polaronic clusters, and are involved to the reorientation-like motion. The polar cluster-polar cluster interaction between such type reorienting polarizations of different clusters can be a possible origin of phase transitions in PMN-like relaxors. Semi-empirical Hartree-Fock calculations of electronic polaron states in some model ABO 3 -systems performed are in a good agreement with the experiment.