Statistical Models of the Polaronic Phase Transition in Manganites
  We propose two statistical models for description the metal-insulator phase transition coupled with paramagnetic-ferromagnetic phase transition in manganites of the type La_{1-x}Sr_xMnO_3. The first one based on the competition of small polarons and delocalized carriers. In the second one the conductivity appears as a result of overlapping of large polarons. We compare our models with the experimental data. 
Igor F.Lyuksyutov(1) and Valery Pokrovsky(1,2) ((1)Department of   Physics, Texas A&M University and (2) Landau Institute fo...