The magnetic instability of Yb2Pd2(In,Sn) in a non-Fermi liquid environment

Various concentrations of the solid solution Yb2Pd2In1-xSnx ranging from x = 0 to 1 with the tetragonal Mo2FeB2-type structure were prepared and their physical properties were studied by means of bulk and spectroscopic measurements as a function of temperature, pressure and magnetic fields. Results deduced from these studies indicate a slight variation of the valency of the Yb ions, from ? ? 2.9 for both border compounds to ? = 3 at x = 0.6. This variation gives rise to the appearance of long range magnetic order in a narrow concentration region around x = 0.6, while both border compounds remain non-magnetic. The outstanding concentration dependence for the ordered regime may be indicative of two quantum critical points, a novel feature not yet observed in Yb compounds.