Absence of small lattice polarons above the Curie temperature in magnetoresist (y=0 and 0.04) - art. no. 052410

It is generally believed that the electrical transport in magnetoresistive manganites above T-C is governed by small polarons associated with large la ttice distortions. We present evidence which confirms the existence of magn etic clusters (polarons) associated with minimal lattice distortions above the Curie temperature. We take advantage of the fact that the Mossbauer spe ctra of the relatively large and slowly fluctuating magnetic polarons consi st of incompletely collapsed magnetic component with extensive wings.