MAGNETIC, XANES AND EXAFS STUDIES OF CECOXSN2 LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-0.5) STANNIDES

The CeCoxSn2 solid solution exists for 0.35 less than or equal to x le ss than or equal to 0.50 and crystallizes in the orthorhombic CeNiSi2- type structure. The b and c unit cell parameters increase with the cob alt rate whereas the a parameter remains steady. Co K-edge EXAFS data analysis led to identify the local environment of cobalt and the resul ts are compared to those determined by X-ray powder diffraction. Above 40-50 K, the temperature dependence of magnetic susceptibility of CeC oxSn2 stannides characterizes a trivalent cerium in agreement with the XANES experiments performed on the Ce L(III)-edge. At low temperature , the Mag.= f(T) (Mag. = magnetization) curves exhibit an anomaly at 3 .3 K, 4 K and 4.5 K for x = 0.4, 0.45 and 0.50 respectively, suggestin g the occurrence of a magnetic ordering transition.