Variable Range Hopping (VRH) Model in Manganese Oxides
This is a study of data analyzing by using a theoretical model for mixed-valence manganites Ln1−xAxMnO3, which exhibit a complex transport behaviour. In the high-temperature (T>TP) paramagnetic insulating regime, the resistivity of samples obeys the T-1/4 law, characteristic of variable range hopping (VRH). We address this kind of transport process as involving variable-range hopping of small polarons, and derive the resistivity expression: .
David J. Fisher
A. Huda "Variable Range Hopping (VRH) Model in Manganese Oxides", Defect and Diffusion Forum, Vols. 303-304, pp. 117-123, 2010