Transport Properties of La_(0.8)Sr_(0.2)Mn_3 and Bi_(0.95)Dy_(0.05)FeO_3 Based (0.5) La_(0.8)Sr_(0.2)MnO_3 + (0.5) Bi_(0.95)by_(0.05)FeO_3 Composite

摘要

Here, we report the structural and low temperature electrical properties of La0.8Sr0.2MnO3 (LSMO), Bi0.95Dy0.05FeO3 (BDFO) and their composite (0.5) LSMO + (0.5) BDFO prepared via solid-state reaction route. X-ray diffraction (XRD) data studies infers that both the compounds LSMO and BDFO are single phased in nature. Further XRD data analysis reveal that both these compounds display their presence in the composite sample. Both the parent samples of the composite were observed to have crystallized in rhombohedral (R3c) structure. The lattice structure was further verified via Raman Spectroscopic measurement technique. Low temperature transport properties study establishes the semiconducting nature of the composite. The dc resistivity data of ferromagnetic mettalic LSMO compound suggests that the electron-electron scattering is predominant in the metallic region whereas the semiconducting region in the composite sample [(0.5) LSMO + (0.5) BDFO] is well described using small polaron hopping and Mott's variable range hopping (VRH) models. Activation energy E-p was found to decrease with increase in magnetic field from 0 to 8T attributed to the decrease in the values of charge localization. The density of states Increases with magnetic field attributed to the suppression of magnetic domain scattering explained via Mott's VRH mechanism. High MR% is observed in both the LSMO sample and the composite one which increases with decrease in temperature.