Effect of the chemical composition on the structural properties antiferromagnetic ternary stannides Ce2Pd2+xSn1-x (0.04(3)<=x<=0.21(4))

The crystal structure of the ternary stannides Ce2Pd2+xSn1-x with 0.04(3) less than or equal to x less than or equal to 0.21(4) was investigated by X-ray diffraction on a single crystal. They crystallize in the new structure deriving from the tetragonal U3Si2-type (space group P4/mbm). The excess of palladium atoms occupies a split position 4e surrounding the replaced tin atom position located at the center of the [Ce-8] tetragonal prism. This defect leads to some changes in the site occupancy of the tin atom. These compounds exhibit interesting magnetic properties: for x = 0.06 two magnetic transitions are observed, one is antiferromagnetic at T-N = 4.7(2) K and the other is ferromagnetic at T-C = 3.0(2) K, whereas only one antiferromagnetic state is found at T-N = 4.2(2) K for x = 0.21. This behavior suggests a stabilization of the antiferromagnetic structure induced by the substitution of palladium for tin atoms.