Structure, magnetic and magnetoresistive properties of La0.7Sr0.3Mn1−xSnxO3 samples (0 ≤ x ≤ 0.20)

Structural, magnetic, and transport properties of polycrystalline La0.7Sr0.3Mn1−xSnxO3 have been experimentally investigated. Single-phase samples were obtained in the range 0 ≤ x ≤ 0.20 by a conventional solid-state reaction method in air. The substitution of Sn4+ at the Mn site results in a significant lattice expansion, a reduction in the Curie temperature TC and in the magnetic moment per Mn ion. In addition, gradual changes in the resistivity behaviour are observed in the Sn-doped samples leading to an enhancement of the magnetoresistance at low doping ratio. The results are analysed in relation to the variation in the Mn3+-O2−-Mn4+ network and to the magnetic disorder caused by the presence of the large and nonmagnetic Sn4+ ions in the Mn sublattice.