Magnetic polaron conduction above the Curie temperature in Fe-doped Pr0.75Sr0.25MnO3

The transport behaviour of Fe-doped Pr0.75Sr0.25MnO3 (PSMFO, Fe = 0.05) is studied by zero-field conductivity probing and Raman spectroscopy. It is revealed that the conductivity of PSMFO above T-m the metal-insulator transition point, shows variable-range-hopping, behaviour instead of the small-polaron mode. The B-2g Raman line at 630 cm(-1) arising from the Mn-O bending and stretching modes undergoes anomalous softening as the temperature is lowered from ambient temperature, indicating a magnetic ordering sequence above T-m. It is demonstrated that the electronic conduction of PSMFO above T-m is governed by magnetic polarons embedded in a matrix of paramagnetic insulating phase.