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《Solid State Communications》1987,63(7):677-679
We have discussed the ultrasonic attenuation and specific heat in the superconducting state of the heavy-fermion compound UPt3 in a quasiparticle picture. Coherence and pair-breaking effect have been taken into account for this system. Our results show that UPt3 is most probably an unconventional s-wave superconductor. 相似文献
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J. F. W. Jansen A. Faas W. J. B. Winter 《Zeitschrift für Physik A Hadrons and Nuclei》1973,261(2):95-116
The decay of two previously reported isomers in195Ir has been investigated with Ge(Li) and Si(Li) detectors by observing β and γ rays as well as conversion electrons in single and coincidence measurements. To about 30 of the 85 observed transitions a multipolarity was assigned. The energies of the gamma rays from195Au were also determined accurately. The decay scheme of195Ir shows 13 new levels in195Pt between 389 and 931 keV. Probable spin and parity assignments could be made to most levels. The results are compared with those of a recent Coulomb excitation study, reaction work and theoretical calculations. 相似文献
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Spin polarization in low-energy electron diffraction from the (111) surface of platinum, which is geometrically unreconstructed, was measured by means of a Mott detector. Corresponding relativistic calculations yield mostly excellent agreement with the data and clearly favour an ion-core scattering potential model containing an energy-dependent exchange approximation. 相似文献
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Yogi M Kitaoka Y Hashimoto S Yasuda T Settai R Matsuda TD Haga Y Onuki Y Rogl P Bauer E 《Physical review letters》2004,93(2):027003
We report on novel antiferromagnetic (AFM) and superconducting (SC) properties of noncentrosymmetric CePt3Si through measurements of the 195Pt nuclear spin-lattice relaxation rate 1/T(1). In the normal state, the temperature (T) dependence of 1/T(1) unraveled the existence of low-lying levels in crystal-electric-field multiplets and the formation of a heavy-fermion (HF) state. The coexistence of AFM and SC phases that emerge at T(N)=2.2 K and T(c)=0.75 K, respectively, takes place on a microscopic level. CePt3Si is the first HF superconductor that reveals a peak in 1/T(1) just below T(c) and, additionally, does not follow the T3 law that used to be reported for most unconventional HF superconductors. We remark that this unexpected SC characteristic may be related to the lack of an inversion center in its crystal structure. 相似文献
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T.M.S. Johnston K.H. Chow S. Dunsiger T. Duty R.F. Kiefl E. Koster W.A. MacFarlane G.D. Morris J. Sonier D.Ll. Williams 《Hyperfine Interactions》1997,106(1-4):71-76
A detailed study has been undertaken of the muon Knight shift in high purity antimony single crystals. No periodic variations
with magnetic field (de Haas–van Alphen oscillations) are observed. The temperature dependence below 175 K is close to that
expected for a Kondo‐like impurity with an anisotropic muon–electron hyperfine interaction. At higher temperatures the paramagnetic
state becomes unstable and a transition occurs to a second state. The longitudinal relaxation rate rises from an apparently
non‐zero value at T=0 to a maximum at 50 K, followed by a slow decline. This leads to a Korringa product which is strongly
temperature dependent.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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《Solid State Communications》1987,62(6):387-390
Quasielastic scattering from spin fluctuations has been observed in UPt3 by Raman spectroscopy. The experiments for wave vectors q≈0 show a nearly temperature independent linewidth for 5 K ⩽ T ⩽ 300 K Complementary to neutron scattering results this establishes the q independence of the spin relaxation rate, indicating the localized nature of the spin fluctuations. A Raman-active phonon near 79 cm-1 (10 meV) shows a drastic increase in line-width with decreasing temperature, demonstrating strong electron-phonon coupling. 相似文献
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de Visser A Graf MJ Estrela P Amato A Baines C Andreica D Gygax FN Schenck A 《Physical review letters》2000,85(14):3005-3008
Transverse-field muon spin relaxation measurements have been carried out on the heavy-fermion superconductor UPt (3) doped with small amounts of Pd. We find that the critical Pd concentration for the emergence of the large-moment antiferromagnetic phase is approximately 0.6 at. %Pd. At the same Pd content, superconductivity is completely suppressed. The existence of a magnetic quantum critical point in the phase diagram, which coincides with the critical point for superconductivity, provides evidence for ferromagnetic spin-fluctuation mediated odd-parity superconductivity, which competes with antiferromagnetic order. 相似文献
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A. Schenck N.K. Sato G. Solt D. Andreica F.N. Gygax M. Pinkpank A. Amato 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,13(2):245-256
We report on transverse field (TF) Muon Spin Rotation (μSR) measurements on a single crystal of the hexagonal heavy fermion
superconductor UNi2Al3 between 5 K and 300 K. From the measured muon Knight shift (KS) in the easy (
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)-plane and along the c-axis we extracted the local magnetic susceptibility tensor [0pt] , which arises from the nearest U-neighbors. By comparison with the bulk susceptibility [0pt] it is found that [0pt] and [0pt] agree well above 150 K but deviate considerably in the basal plane below 150 K, due to the disturbance introduced by the
. We succeed in reproducing both [0pt] and [0pt] on the basis of a crystalline electric field (CEF)-approach assuming U to be in the tetravalent state. The disturbance introduced by the affects the CEF-Hamiltonian in an expected manner, suggesting strongly that a CEF-picture implying a rather local 5
f-electron wave function is indeed valid. Reanalyzing older data on UPd2Al3 we arrive at the same conclusion. A necessary condition for extracting the local susceptibility was the knowledge of the
-site, this information was derived from the analysis of the TF-relaxation rates. At low temperatures we found about 30% of
the implanted at the d-site and none at this site above 200 K. The majority fraction was found to be in a tunneling state over six m (or k)-sites around the b-site. No long range diffusion was seen up to room temperature.
Received 20 April 1999 相似文献
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