Large positive magnetoresistance effect below Curie temperature in In1.90 − xMn0.1SnxO3

We report on the magnetoresistance (MR) and magnetic properties of In1.90−xMn0.1SnxO3 (0≤x ≤0.06) oxide. All samples were found to be ferromagnetic below TC=46 K. Sn doping changed In1.90Mn0.1O3 from an insulator to a highly conducting phase at 300 K. A positive MR effect was observed over a wide temperature range just below TC. Calculated MR values reached a maximum of 20% at 5 K. A change in the MR effect, from positive to negative, occurred under magnetic field H>4 T at 5 K. The results of x-ray absorption near-edge spectroscopy indicated that Mn ions are present both as Mn2+ and Mn4+.