Study of some co-precipitated manganite perovskite samples-doped iron |
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| Authors: | AG Mostafa EK Abdel-Khalek WM Daoush SF Moustfa |
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| Institution: | 1. Mössbauer Laboratory, Physics Department, Faculty of Science, Al Azhar University, Nasr City, Cairo, Egypt;2. Powder Technology Department, Central Metallurgy R & D Institute, Helwan, Cairo, Egypt |
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| Abstract: | Polycrystalline La0.70Sr0.30Mn1−yFeyO3 (0.05?y?0.07) samples are prepared by the co-precipitation method and have been studied. The substitution of Mn3+ by Fe3+ reduces the number of available hopping sites for the Mn eg(↑) electron and suppresses the double exchange (DE), resulting in the reduction of the metal–semiconductor transition temperature (TP) and the flux density saturation (Bs). Low-temperature resistivity (ρ) data (below TP) well fit with the relation ρ(T)=ρ0+ρ2T2, indicating the importance of grain/domain boundary effects and electron–electron scattering processes in the conduction of these materials. On the other hand, at high temperature (TP<T<θD/2) conductivity data satisfy the variable range hopping (VRH) model. For T>θD/2 the small polaron hopping model is more appropriate than the VRH model. |
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| Keywords: | Manganite Co-precipitation X-ray diffraction Mö ssbauer spectroscopy Electrical and magnetic property |
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