Detailed temperature dependence of both superconducting gaps was obtained directly by means of SnS-Andreev spectroscopy. The Delta sigma,pi(T) -curves were shown to be deviated from standard BCS-like behavior, due to k-space proximity effect between sigma - and pi - condensates, which could give a key to experimental determination of interband electron-phonon coupling constants. For the first time, an excellent qualitative agreement with theoretical predictions of Nicol and Carbotte, and Moskalenko and Suhl was shown. dI(V)/dV-spectra of SnS-Andreev contacts based on MgB2 samples (with defects of crystal structure), and Mg(Al)B2 polycrystalline samples (with the local critical temperatures Tc variation 10 K < Tc < 37 K) were studied by means of the break-junction technique within the temperature range 4.2 K < T < Tc.
تحميل البحث