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Author (up) Durán, C.; Esquinazi, P.; Luzuriaga, J.; Brandt, E.H. doi  openurl
  Title Bc1 of high-Tc La1.8Sr0.2CuO4 and amorphous Zr70Cu30 superconductors measured by a vibrating reed Type Journal Article
  Year 1987 Publication Physics Letters A Abbreviated Journal Phys. Lett. A  
  Volume 123 Issue 9 Pages 485-488  
  Keywords Zr70Cu30; ZIRCONIUM COPPER ALLOYS – Amorphous  
  Abstract The lower critical field Bc1 of the high-Tc superconductor La1.8Sr0.2CuO4 (Tc=40 K, Bcless-than-or-equals, slant7.7 mT) and of amorphous Zr70Cu30 (Tc=2.6K, Bc1less-than-or-equals, slant3.8 mT) is obtained from the resonance frequency ?/2? of a vibrating reed made of these materials. At applied magnetic fields Ba<Bc1, ?(Ba)=?i(Ba) as predicted for an ideally diamagnetic reed. Above Bc1 we observe a reversible linear law ?2??2inot, vert, similarB2a?B2c1. This allows a simple definition of Bc1 even in ceramic superconductors into which flux starts to penetrate at Bamuch less-thanBc1 due to their granular structure.  
  Address  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0375-9601 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:A1987K407100012 Approved no  
  Call Number BT @ hernan @ Serial 269  
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Author (up) Esquinazi, P.; de la Cruz, F. url  doi
openurl 
  Title Phonon thermal conductivity limited by electron scattering in amorphous Zr70Cu30 Type Journal Article
  Year 1983 Publication Physical Review B Abbreviated Journal Phys. Rev. B  
  Volume 27 Issue 5 Pages 3069-3072  
  Keywords Zr70Cu30; superconductivity; amorphous  
  Abstract The low-temperature thermal conductivity of amorphous Zr70Cu30 is investigated. The lattice thermal conductivity as limited by electrons in the superconducting state has been obtained at temperatures close to Tc. This has allowed for the first time the verification of the temperature dependence of the phonon conductivity as predicted by Bardeen, Rickayzen, and Tewordt. The analysis of the data in the normal and superconducting state shows that Matthiessen's rule can be used in amorphous metals to separate the different scattering processes.  
  Address  
  Corporate Author Thesis  
  Publisher American Physical Society Place of Publication Editor  
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  Notes Approved no  
  Call Number BT @ pedrazp @ 10.1103/PhysRevB.27.3069 Serial 560  
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Author (up) Esquinazi, P.; Luzuriaga, J. url  openurl
  Title Annealing effects on the sound velocity and internal friction in the superconducting and normal states of the Cu30Zr70 amorphous alloy Type Journal Article
  Year 1988 Publication Physical Review B Abbreviated Journal  
  Volume 37 Issue 13 Pages 7819-7831  
  Keywords Zr70Cu30  
  Abstract By means of the vibrating-reed technique we have measured the evolution upon low-temperature annealing of the internal friction Q-1 and sound velocity v of the Cu30Zr70 amorphous alloy between 0.1 and 10 K. With an applied magnetic field of 5.6 T we measured also the normal-state behavior of both properties. Upon annealing, the internal friction and the slope of the logarithmic temperature dependence of v in the superconducting state decrease, in agreement with the standard tunneling model. Our results indicate that with thermal treatments, the coupling constant between tunneling systems (TSs) and phonons decreases, and the density of states of the TS remains constant or decreases, at most 25%, in the fully relaxed state, which is in agreement with published specific-heat results in these materials. From our data we conclude that the coupling constant between the TS and phonons should be very sensitive to the relaxed state of the disordered structure. The sound-velocity behavior strongly indicates that relaxation processes up to 10 K involve the interaction with the TS. A well-defined change of slope in v at the superconducting critical temperature Tc is observed in the as-quenched and the first relaxed state, which cannot be explained with the standard tunneling model and the Korringa-like relaxation rate between the TS and electrons. Several features observed in the superconducting and normal states lead to the conclusion that the TS-electron interaction problem remains unsolved.  
  Address Centro Atómico Bariloche, Instituto Balseiro, 8400 Bariloche, Argentina  
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  ISSN 01631829 (ISSN) ISBN Medium  
  Area Expedition Conference  
  Notes Cited By (since 1996): 9; Export Date: 28 April 2009; Source: Scopus; doi: 10.1103/PhysRevB.37.7819; Language of Original Document: English; Correspondence Address: Esquinazi, P.; Centro Atmico Bariloche; Instituto Balseiro 8400 Bariloche, Argentina Approved no  
  Call Number BT @ luzuriag @ Serial 494  
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Author (up) Guimpel, J.; de la Cruz, F. url  doi
openurl 
  Title Electrical resistivity of amorphous Zr70Cu30 and the Kondo like model Type Journal Article
  Year 1982 Publication Solid State Communications Abbreviated Journal Solid State Commun.  
  Volume 44 Issue 7 Pages 1045-1046  
  Keywords Zr70Cu30; superconductivity; electrical resistivity; ZIRCONIUM COPPER ALLOYS  
  Abstract Electrical resistivity measurements of amorphous Zr70Cu30 as a function of the concentrations of two level systems show that a Kondo like theory cannot explain the observed temperature dependence.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0038-1098 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ pedrazp @ Serial 540  
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