Structural, electrical, magnetic and microstructural behavior of the La_0.7Sr_{0.3−<i>x</i>}Hg_<i>x</i>MnO₃(0≤<i>x</i>≤0.3) system

Abstract

We report a detailed investigation on the polycrystalline samples of the colossal magnetoresistance system La0.7Sr0.3−xHgxMnO3 (0≤x≤0.3). The emphasis is put on identifying the role of Hg in the perovskite matrix. We have used the neutron diffraction technique for structural analysis. The issues pertaining to composition-dependent variations in parameters like average ionic radii, tolerance factor, variance, bond length, bond angle, lattice parameters and cationic vacancies have been addressed. The low temperature resistivity measurement and subsequent curve fitting are used to explore the contributions from various disorders and interactions. The samples with x = 0.3 composition showed distinct electrical behavior and magnetoresistance up to 46% around T = 198 K. The low temperature neutron diffraction data revealed ferromagnetic character of the samples. All the samples displayed similar microstructures. The variations in the electrical and magnetic properties are attributed to origination from cationic disorders.