Influence of Ho substitution on the structural and magnetic properties of DyCu5Sn

Several samples from the homogeneity range of the solid solution Dy1-xHoxCu5Sn (x = 0-0.1) were prepared by arc melting of the elements and annealed first at 1100 K and then at 870 K. The crystal structure of DyCu5Sn was solved from single-crystal X-ray diffraction data, and Rietveld refinements of X-ray powder diffraction data were carried out to analyze the evolution of the lattice parameters in the solid solution. The Dy1-xHoxCu5Sn phase crystallizes with the structure type CeCu5Au (an ordered variant of the CeCu6 type). The replacement of Dy by Ho is accompanied by a decrease of the volume of the unit cell. The magnetic behavior of the Dy1-xHoxCu5Sn intermetallics was studied by magnetic susceptibility (χ) measurements in the temperature range 1.8-400 K. Contrary to earlier reports a paramagnetic Curie temperature of -3.9 K was found for DyCu5Sn, but the magnetic behavior of the sample Dy0.9Ho0.1Cu5Sn, with a critical temperature near 0 K, can be described by a quantum phase transition associated with an antiferromagnetic transformation.