Point-contact study of the role of non-magnetic impurities and disorder in the superconductivity of MgB2 (Articolo in rivista)

Type
Label
  • Point-contact study of the role of non-magnetic impurities and disorder in the superconductivity of MgB2 (Articolo in rivista) (literal)
Anno
  • 2007-01-01T00:00:00+01:00 (literal)
Alternative label
  • Daghero, D; Calzolari, A; Delaude, D; Gonnelli, RS; Tortello, M; Ummarino, GA; Stepanov, VA; Zhigadlo, ND; Karpinski, J; Putti, M (2007)
    Point-contact study of the role of non-magnetic impurities and disorder in the superconductivity of MgB2
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Daghero, D; Calzolari, A; Delaude, D; Gonnelli, RS; Tortello, M; Ummarino, GA; Stepanov, VA; Zhigadlo, ND; Karpinski, J; Putti, M (literal)
Pagina inizio
  • 975 (literal)
Pagina fine
  • 976 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
  • 460 (literal)
Note
  • ISI Web of Science (WOS) (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • Politec Torino, CNISM, Dipartimento Fis, I-10129 Turin, Italy; Russian Acad Sci, Lebedev Phys Inst, Moscow 119991, Russia; ETH, Solid State Phys Lab, CH-8093 Zurich, Switzerland; Univ Genoa, CNR, INFM,LAMIA, Dipartimento Fis, I-16146 Genoa, Italy (literal)
Titolo
  • Point-contact study of the role of non-magnetic impurities and disorder in the superconductivity of MgB2 (literal)
Abstract
  • We summarize and compare the results obtained by point-contact spectroscopy (PCS) in high-quality single crystals and polycrystals of MgB2 with partial Al or C substitutions or irradiated with neutrons. We determined the values of the gaps Delta(sigma) and Delta(pi) by fitting the conductance curves of point contacts in the Andreev-reflection regime with the generalized BTK model. We always studied the temperature and magnetic-field dependencies of the conductance curves, so as to determine the critical temperature of the contact, T-c(A) and highlight whether one or two gaps were present. The dependence of the gaps on TcA shows a dominant effect of the band filling not only in Mg1-xAlxB2 and Mg(B1-xCx)(2) but also, unexpectedly, in irradiated MgB2. The increase in interband scattering is instead smaller than expected in Al-doped and irradiated MgB2 but is very large in C-doped single crystals, probably for extrinsic effects. (c) 2007 Elsevier B.V. All rights reserved. (literal)
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