XANES investigation of novel lanthanide-doped CuCr_(0.99)Ln_(0.01)S_2(Ln = La, Ce) solid solutions

摘要

The study of the valence state, local environment structure and magnetic properties of novel type CuCr_(0.99)Ln_(0.01)S_2 (Ln = La, Ce) solid solutions was carried out using X-ray absorption spectroscopy, finite difference method simulations and static magnetic susceptibility measurements. The good agreement between experimental and calculated data indicates that cati-onic substitution does not lead to significant changes in the copper, chromium and sulfur local environment character and electronic density distribution. The copper atoms were found to be in Cu~+ oxidation state, the sulfur atoms-in S~(2-) oxidation state and the chromium atoms-in Cr~(3+) state. The cationic substitution of chromium by lanthanum and cerium in CuCrS_2 does not significantly affect the effective magnetic moment and exchange interactions character. The lanthanum-doped CuCr_(0.99)Ln_(0.01)S_2 solid solution demonstrates the Seebeck coefficient value 4 times greater than for CuCrS_2-matrix at 500 K.