Electrical and magneto transport properties of La0.8−x Ca x Sr0.1Ag0.1MnO3 (x = 0.1, 0.2, 0.3)

Abstract

Lanthanum-based manganites La 0.8−x Ca x Sr 0.1 Ag 0.1 MnO 3 (x = 0.1, 0.2, 0.3) doped with both alkaline metal (Ag) and alkaline earth (Ca and Sr) elements are studied. The structural characterization of polycrystalline samples synthesized through low temperature nitrate route confirms orthorhombic structure for all the investigated samples. The morphology of crystal grains shows that the grains are nearly uniform in size and spherical. Electrical resistivity of samples reveal two transition peaks typical of Ag-doped lanthanum-based manganites. Significant room temperature magneto resistivity (MR) is observed for all the samples. MR is found to behave almost linearly with temperature for x = 0.1 sample for different magnetic field strengths in contrast to plateau type behaviour observed for x = 0.3 sample. Standard temperature-dependent resistivity models such as small polaron and variable range hopping are used to fit the resistivity data in the high temperature range. In the low temperature domain, the resistivity data could be fitted to a model which combines electron-electron scattering and weak localization.