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muSR and NMR in f-electron non-Fermi liquid materials

D. E. MacLaughlin·M. S. Rose·Ben-Li Young·O. O. Bernal·R. H. Heffner·G. D. Morris·K. Ishida·G. J. Nieuwenhuys·J. E. Sonier
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Abstract

Magnetic resonance (muSR and NMR) studies of f-electron non-Fermi-liquid (NFL) materials give clear evidence that structural disorder is a major factor in NFL behavior. Longitudinal-field muSR relaxation measurements at low fields reveal a wide distribution of muon relaxation rates and divergences in the frequency dependence of spin correlation functions in the NFL systems UCu_{5-x}Pd_x and CePtSi_{1-x}Ge_x. These divergences seem to be due to slow dynamics associated with quantum spin-glass behavior, rather than quantum criticality as in a uniform system, for two reasons: the observed strong inhomogeneity in the muon relaxation rate, and the strong and frequency-dependent low-frequency fluctuation observed in U(Cu,Pd)_5 and CePt(Si,Ge). In the NFL materials CeCu_{5.9}Au_{0.1}, Ce(Ru_{0.5}Rh_{0.5})_2Si_2, CeNi_2Ge_2, and YbRh_2Si_2 the low-frequency weight of the spin fluctuation spectrum is much weaker than in the disordered NFL systems.

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D. E. MacLaughlin, M. S. Rose, Ben-Li Young, O. O. Bernal, R. H. Heffner, G. D. Morris, K. Ishida, G. J. Nieuwenhuys, J. E. Sonier. 2002-07-18. muSR and NMR in f-electron non-Fermi liquid materials. https://doi.org/10.1016/s0921-4526(02)01637-x

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