Giant magnetoresistance in bulk samples of LaMnO
نویسندگان
چکیده
Abstract, Magnetoresistance (MR) in bulk samples of LaMnO 3 has been investigated by varying the Mn 4+ content from 10 to 33 per cent by chemical means, without aliovalent doping. With the increase in Mn 4 + content, the structure of LaMnO 3 changes first from orthorhombic to rhombohedral and then to cubic and the material becomes increasingly ferromagnetic, exhibiting a resistivity maximum akin to an insulator-metal transition at Tpcak, just below the ferromagnetic T c. The magnitude of MR is highest in the cubic sample (with 33% Mn 4÷) around the Tpc,k, and negligible in the non-magnetic orthorhombic sample (12% Mn4+).
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