Specific heat and magnetic susceptibility of nearly stoichiometric and homogeneous Nb 3 Al
作者： A. Junod , J.-L. Jorda , M. Pelizzone , J. Muller
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摘要: A15-type Nb/sub 3/Al has been characterized in the recent past as a ''high-T/sub c/, low-..gamma.. superconductor,'' where ..gamma.. is electronic specific-heat coefficient. We show that this statement should be revised, previous analyses simply reflecting imperfect metallurgical state. succeeded preparing homogeneous, nearly stoichiometric, bulk and reinvestigated specific heat (from 1 to 50 K) magnetic susceptibility (19--300 highly ordered slightly disordered condition. The new results exhibits high density of states (..gamma.. = 11.4 mJ K/sup -2/ g-at./sup -1/, N(0)approx. =0.91 eV/sup -1/ atom/sup spin/sup -1/). Information provided on moments phonon spectrum those electron-phonon spectral function, thermodynamical critical field, energy gap 2..delta..(0). present experiments further establish only weak exchange enhancement susceptibility; spin fluctuations may therefore safely neglected. Specific-heat data are also reported for neighboring sigma-phase 2/Al.
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