Abstract
Li-substituted perovskites La1−xLixMnO3 (LLMO; 0.05≤x≤0.25) were investigated by X-ray diffraction, electric resistivity and magnetoresistance (MR) measurements. All samples show a rhombohedral structure (space group R3̄c) at room temperature. The cell parameters a, c and the unit cell volume decrease with increasing Li content. A metal to insulator transition is observed for all the samples. The metal to insulator transition temperature TMI appears of all the samples shifts to a lower temperature and the resistivity increases with increasing Li content. The resistivity data in the metallic region (below TMI) is well fitted (for x≤0.15) with the expression corresponding to electron–electron scattering mechanism. The high temperature (T>θD/2, θD is Debye temperature) resistivity data, both in presence and in absence of magnetic field, is found to be quite well described by the adiabatic small polaron-hopping model. The lower temperature (between TMI and θD/2) resistivity data of all the samples is found to be in accordance with the variable range hopping model. A nearly constant MR=50% with the application of magnetic field of 0.5T over the measured temperature zone between 313 and 79K was observed for low doping Li-content (x≤0.10), which is very beneficial for practical applications.
Published Version
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