SPIN-GLASS BEHAVIOR IN DOPED AND PURE UPT3 - A POSSIBLE KEY

While studying doped UPt3, we employed the standard technique of measu ring chi(dc) in both zero-field-cooled and field-cooled states to chec k for possible spin glass behaviour. The results of these studies lead to the discovery that nominally pure UPt3 itself has a tendency towar ds spin glass behaviour. This instability makes for very sample-depend ent properties (as is typical in spin glasses), especially for superco nductivity, and is likely the long-sought ''hidden parameter'' linking a large number of the unusual behaviours in UPt3. Thus, the measured spin glass behaviour in UPt3 reported here can explain the extreme sam ple dependence of T-c, the observed aging effect on T-c, and the destr uction of superconductivity in UPt3 by grinding. In addition, the disc overy of spin glass behaviour in UPt3 may have implications for unders tanding the small-moment magnetism below 5 K and the double supercondu cting transition in some samples, as well as helping to explain the kn own important role of defects in UPt3.