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Shu L, MacLaughlin DE, Varma CM, Bernal OO, Ho PC, Fukuda RH, Shen XP, Maple MB. Landau renormalizations of superfluid density in the heavy-fermion superconductor CeCoIn5. Phys Rev Lett 2014; 113:166401. [PMID: 25361270 DOI: 10.1103/physrevlett.113.166401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Indexed: 06/04/2023]
Abstract
The formation of heavy-fermion bands can occur by means of the conversion of a periodic array of local moments into itinerant electrons via the Kondo effect and the huge consequent Fermi-liquid renormalizations. Leggett predicted for liquid (3)He that Fermi-liquid renormalizations change in the superconducting state, leading to a temperature dependence of the London penetration depth Λ quite different from that in BCS theory. Using Leggett's theory, as modified for heavy fermions, it is possible to extract from the measured temperature dependence of Λ in high quality samples both Landau parameters F(0)(s) and F(1)(s); this has never been accomplished before. A modification of the temperature dependence of the electronic specific heat C(el), related to that of Λ, is also expected. We have carefully determined the magnitude and temperature dependence of Λ in CeCoIn(5) by muon spin relaxation rate measurements to obtain F(0)(s) = 36 ± 1 and F(1)(s) = 1.2 ± 0.3, and we find a consistent change in the temperature dependence of C(el). This, the first determination of F(1)(s) with a value ≪ F(0)(s) in a heavy-fermion compound, tests the basic assumption of the theory of heavy fermions, that the frequency dependence of the self-energy is much more important than its momentum dependence.
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Affiliation(s)
- Lei Shu
- State Key Laboratory of Surface Physics, Department of Physics, Fudan University, Shanghai 200433, People's Republic of China
| | - D E MacLaughlin
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
| | - C M Varma
- Department of Physics and Astronomy, University of California, Riverside, California 92521, USA
| | - O O Bernal
- Department of Physics and Astronomy, California State University, Los Angeles, California 90032, USA
| | - P-C Ho
- Department of Physics, California State University, Fresno, California 93740, USA
| | - R H Fukuda
- Department of Physics, California State University, Fresno, California 93740, USA
| | - X P Shen
- State Key Laboratory of Surface Physics, Department of Physics, Fudan University, Shanghai 200433, People's Republic of China
| | - M B Maple
- Department of Physics, University of California, San Diego, La Jolla, California 92093, USA
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Zhao S, MacLaughlin DE, Bernal OO, Mackie JM, Marques C, Janssen Y, Aronson MC. Magnetic transition and spin fluctuations in the unconventional antiferromagnetic compound Yb₃Pt₄. J Phys Condens Matter 2011; 23:094220. [PMID: 21339573 DOI: 10.1088/0953-8984/23/9/094220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Muon spin rotation and relaxation measurements have been carried out on the unconventional antiferromagnet Yb3Pt4. Oscillations are observed below T(N) = 2.22(1) K, consistent with the antiferromagnetic (AFM) Néel temperature observed in bulk experiments. In agreement with neutron diffraction experiments the oscillation frequency ω(μ)(T)/2π follows an S = 1/2 mean-field temperature dependence, yielding a quasistatic local field of 1.71(2) kOe at T = 0. A crude estimate gives an ordered moment of ∼ 0.66 μ(B) at T = 0, comparable to 0.81 μ(B) from neutron diffraction. As T-->T(N) from above the dynamic relaxation rate λ(d) exhibits no critical slowing down, consistent with a mean-field transition. In the AFM phase a T-linear fit to λ(d)(T), appropriate to a Fermi liquid, yields highly enhanced values of λ(d)/T and the Korringa constant K(μ)(2)T/λ(d), with K(μ) the estimated muon Knight shift. A strong suppression of λ(d) by applied field is observed in the AFM phase. These properties are consistent with the observed large Sommerfeld-Wilson and Kadowaki-Woods ratios in Yb3Pt4 (although the data do not discriminate between Fermi-liquid and non-Fermi-liquid states), and suggest strong enhancement of q≈0 spin correlations between large-Fermi-volume band quasiparticles in the AFM phase of Yb3Pt4.
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Affiliation(s)
- S Zhao
- Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA
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MacLaughlin DE, Sonier JE, Heffner RH, Bernal OO, Young BL, Rose MS, Morris GD, Bauer ED, Do TD, Maple MB. Muon spin relaxation and isotropic pairing in superconducting PrOs4Sb12. Phys Rev Lett 2002; 89:157001. [PMID: 12366013 DOI: 10.1103/physrevlett.89.157001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2002] [Indexed: 05/23/2023]
Abstract
Transverse-field muon-spin rotation measurements in the vortex-lattice of the heavy-fermion (HF) superconductor PrOs4Sb12 yield a temperature dependence of the magnetic penetration depth lambda indicative of an isotropic or nearly isotropic energy gap. This is not seen to date in any other HF superconductor and is a signature of isotropic pairing symmetry, possibly related to a novel nonmagnetic "quadrupolar Kondo" HF mechanism in PrOs4Sb12. The T=0 relaxation rate sigma(s)(0)=0.91(1) micros(-1) yields an estimated magnetic penetration depth lambda(0)=3440(20) A, which is considerably shorter than in other HF superconductors.
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Affiliation(s)
- D E MacLaughlin
- Department of Physics, University of California, Riverside 92521-0413, USA
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Bernal OO, Rodrigues C, Martinez A, Lukefahr HG, MacLaughlin DE, Menovsky AA, Mydosh JA. 29Si NMR and hidden order in URu2Si2. Phys Rev Lett 2001; 87:196402. [PMID: 11690437 DOI: 10.1103/physrevlett.87.196402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2001] [Indexed: 05/23/2023]
Abstract
Below T(N) approximately 17 K the 29Si NMR line in URu2Si2 exhibits a previously unobserved field-independent nearly isotropic contribution to the linewidth, which increases to approximately 12 G as T-->0. We argue that this feature does not arise from static freezing of the U-spin magnetization, but is due to coupling between 29Si spins and a hidden order parameter. We discuss time-reversal symmetry-breaking orbital antiferromagnetism and indirect nuclear spin-spin interactions as possible coupling mechanisms. Further NMR experiments and theoretical calculations are suggested.
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Affiliation(s)
- O O Bernal
- Department of Physics and Astronomy, California State University, Los Angeles, California 90032, USA
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MacLaughlin DE, Bernal OO, Heffner RH, Nieuwenhuys GJ, Rose MS, Sonier JE, Andraka B, Chau R, Maple MB. Glassy spin dynamics in non-fermi-liquid UCu5-xPdx, x = 1.0 and 1.5. Phys Rev Lett 2001; 87:066402. [PMID: 11497836 DOI: 10.1103/physrevlett.87.066402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2000] [Indexed: 05/23/2023]
Abstract
Local f-electron spin dynamics in the non-Fermi-liquid heavy-fermion alloys UCu5-xPdx, x = 1.0 and 1.5, have been studied using muon spin-lattice relaxation. The sample-averaged asymmetry function G(t) indicates strongly inhomogeneous spin fluctuations and exhibits the scaling G(t,H) = G(t/H(gamma)) expected from glassy dynamics. At 0.05 K gamma(x = 1.0) = 0.35+/-0.1, but gamma(x = 1.5) = 0.7+/-0.1. This is in contrast to inelastic neutron scattering results, which yield gamma = 0.33 for both concentrations. There is no sign of static magnetism approximately greater than 10(-3)(B)/U ion in either material above 0.05 K. Our results strongly suggest that both alloys are quantum spin glasses.
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Affiliation(s)
- D E MacLaughlin
- Department of Physics, University of California, Riverside, California 92521-0413, USA
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Bernal OO, MacLaughlin DE, Amato A, Feyerherm R, Gygax FN, Schenck A, Heffner RH, Le LP, Nieuwenhuys GJ, Andraka B, Löhneysen H, Stockert O, Ott HR. Kondo disorder and non-Fermi-liquid behavior in UCu5-xPdx and CeCu5.9Au0.1. Phys Rev B Condens Matter 1996; 54:13000-13008. [PMID: 9985158 DOI: 10.1103/physrevb.54.13000] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Bernal OO, MacLaughlin DE, Lukefahr HG, Andraka B. Copper NMR and Thermodynamics of UCu5-xPdx: Evidence for Kondo Disorder. Phys Rev Lett 1995; 75:2023-2026. [PMID: 10059189 DOI: 10.1103/physrevlett.75.2023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Lukefahr HG, Bernal OO, MacLaughlin DE, Seaman CL, Maple MB, Andraka B. Estimation of the intrinsic magnetic susceptibility of Y1-xUxPd3 and UCu5-xPdx. Phys Rev B Condens Matter 1995; 52:3038-3041. [PMID: 9981408 DOI: 10.1103/physrevb.52.3038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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