Weak quasistatic magnetism in the frustrated Kondo lattice Pr2Ir2O7

✍ Scribed by D.E. MacLaughlin; Y. Ohta; Y. Machida; S. Nakatsuji; G.M. Luke; K. Ishida; R.H. Heffner; Lei Shu; O.O. Bernal

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 259 KB
• Volume: 404
• Category: Article
• ISSN: 0921-4526
• DOI: 10.1016/j.physb.2008.11.167

✦ Synopsis

Muon spin relaxation experiments have been performed in the pyrochlore iridate Pr 2 Ir 2 O 7 for temperatures in the range 0.025-250 K. Kubo-Toyabe relaxation functions are observed up to \200 K, indicating static magnetism over this temperature range. The T ! 0 static muon spin relaxation rate Dð0Þ % 8 ms À1 implies a weak quasistatic moment ð$0:1m B Þ. The temperature dependence of D is highly nonmean-field-like, decreasing smoothly by orders of magnitude but remaining nonzero for ToT f . The data rule out ordering of the full Pr 3þ CEF ground-state moment ð3:0m B Þ down to 0.025 K. The weak static magnetism is most likely due to hyperfine-enhanced 141 Pr nuclear magnetism. The dynamic relaxation rate l increases markedly below $20 K, probably due to slowing down of spin fluctuations in the spin-liquid state. At low temperatures l is strong and temperature-independent, indicative of a high density of low-lying spin excitations as is common in frustrated antiferromagnets.