Magnetic polarons mediated percolative phase transition in manganites

We discuss possible models for describing the metal-insulator phase transit ion coupled with paramagnetic-ferromagnetic phase transition in manganites. We argue that current models have apparent drawbacks. As a way to explain experiments we introduce the magnetic (large) polaron model. In this model, the conductivity appears as a result of percolative overlapping of magneti c polarons which coexist with small (Jahn-Teller) polarons. We compare this model with the experimental data.