Spin glass behaviour in doped and pure UPt₃ — A possible key

Institut für Physik, Universität Augsburg, Memminger Str. 6, 86159 Augsburg, Germany

Received: 14 March 1996
Accepted: 6 June 1996

Abstract

While studying doped , we employed the standard technique of measuring in both zero-field–cooled and field-cooled states to check for possible spin glass behaviour. The results of these studies lead to the discovery that nominally pure itself has a tendency towards spin glass behaviour. This instability makes for very sample-dependent properties (as is typical in spin glasses), especially for superconductivity, and is likely the long-sought "hidden parameter" linking a large number of the unusual behaviours in . Thus, the measured spin glass behaviour in reported here can explain the extreme sample dependence of , the observed aging effect on , and the destruction of superconductivity in by grinding. In addition, the discovery of spin glass behaviour in UPt ₃ may have implications for understanding the small-moment magnetism below 5 K and the double superconducting transition in some samples, as well as helping to explain the known important role of defects in .