Susceptibility inhomogeneity and non-Fermi liquid behavior in

✍ Scribed by D.E. MacLaughlin; M.S. Rose; O.O. Bernal; R.H. Heffner; G.J. Nieuwenhuys; R. Chau; M.B. Maple

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 197 KB
• Volume: 374-375
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2005.11.044

✦ Synopsis

Transverse-field mSR shifts and relaxation rates have been measured in the non-Fermi liquid (NFL) alloy system UCu 5Àx Pt x , x ¼ 1:0, 1.5, and 2.5. At low temperatures the fractional spread in Knight shifts dK=K % dw=w is \2 for x ¼ 1, but is only half this value for x ¼ 1:5 and 2.5. In a disorder-driven scenario where the NFL behavior is due to a broadly distributed (Kondo or Griffiths-phase cluster) characteristic energy E, our results indicate that dE=E av % ðdK=KÞ T!0 is similar for UCu 5Àx Pd x (x ¼ 1 and 1.5) and UCu 4 Pt, but is reduced for UCu 5Àx Pt x , x ¼ 1:5 and 2.5. This reduction is due to a marked increase of E with increasing x; the spread dE is found to be roughly independent of x. Our results correlate with the observed suppression of other NFL anomalies for x41 in UCu 5Àx Pt x but not in UCu 5Àx Pd x , and are further evidence for the importance of disorder in the NFL behavior of both these alloy systems.