Influence of silver doping on the electrical and magnetic behavior of La0.7Ca0.3MnO3 manganites

A systematic investigation of structural, magnetic and magnetotransport behavior of La0.7Ca0.3−xAgxMnO3 manganites has been undertaken. The X-ray diffraction shows a structural transformation from orthorhombic to rhombohedral with increasing Ag concentration. The undoped and 10% Ag substituted samples exhibit double transition in M–T curves. The electrical resistivity in the entire temperature range is fitted to effective medium approximation and phase separation models. The sign of S changes from negative to positive with increase in Ag doping. The low temperature thermopower data has been fitted to an equation containing diffusion, magnon drag and phonon drag terms. The paramagnetic insulting part of the TEP data has been analyzed using small polaron hopping mechanism.

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