X-Ray Induced Structural Change and Electrical Conduction in Spinel Compound CuIr₂S₄(Current Topics)

Abstract

A spinel compound CuIr₂S₄ shows a metal-insulator transition accompanied by a structural transition at 230K and becomes an insulator with a triclinic structure below the transition temperature. This is due to a simultaneous charge ordering of Ir³⁺ and Ir⁴⁺ and spin-dimerization of Ir⁴⁺. We found that X-ray irradiation induces a structural change from triclinic to tetragonal below ∼50K and reduces the electrical resistivity by at least three orders magnitude.