Non-Fermi-liquid behavior of YbCu5-xAlx

A valency change in YbCu5-xAlx from nu approximate to 2.2(x=0) to nu=3(x=2) causes a magnetic instability near a critical concentration x(cr)approximate to 1.5 Alloys in the vicinity of x(cr) exhibit typical non-Fermi-liquid properties like a negative logarithmic contribution to the specific heat or substantial deviations of the electrical resistivity from a T-2 behavior. Both pressure and alloying in this series bring about a strong reduction of the Kondo temperature T-K; the crystal-held interaction and the interatomic exchange gain therefore importance and magnetic order becomes possible beyond x(cr).