An Investigation Of The Ferromagnetic Insulating State Of Manganites

Abstract

Electrical conductance in the ferromagnetic insulating (FMI) phase of manganites has been experimentally investigated. The investigations were performed on single crystals of compositions La0.82Ca0.18MnO3 and Nd0.7Pb0.3MnO3. The nature of electrical conductance is determined to be Shklovskii–Efros variable range hopping (SE–VRH). Further, at high bias levels, non–linear conductance (NLC) is observed. A “hot electron” model, that quantitatively explains the bias and temperature dependence of the NLC, consistent with the SE–VRH nature of electrical conductance, is presented. The limits of validity of the model are discussed.