Inhaltszusammenfassung

Systematic studies on the temperature- and magnetic field-dependent electrical resistivity of superconducting amorphous metals such as Zr---X (X = Rh, Ru, Cu, Ir, Ni, Fe) and Mo---B have reveealed simple emperical rules exerted between their bulk and fluctuating superconductivity. All the materials with high resistivity (around 150?300 microohms cm) show the monotonic increase of (T) on cooling and then exhibit a broad peak at the temperature Tp. A quite simple correlation between Tp and Tc ...Systematic studies on the temperature- and magnetic field-dependent electrical resistivity of superconducting amorphous metals such as Zr---X (X = Rh, Ru, Cu, Ir, Ni, Fe) and Mo---B have reveealed simple emperical rules exerted between their bulk and fluctuating superconductivity. All the materials with high resistivity (around 150?300 microohms cm) show the monotonic increase of (T) on cooling and then exhibit a broad peak at the temperature Tp. A quite simple correlation between Tp and Tc is found, i.e., Tp = (2.75±0.25)Tc. All the measured materials with an upper critical-field gradient ?dHc2/dT)Tc of 2?3 T/K show the magnetic-field-induced saturation of the resistivity at the field Hs. Although Hs depends sensitively on temperatures especially near Tc, the correlation H=(2±0.5)Hc2 between Hs and Hc2, is found to hold at low temperatures, . The presence of both Tp and Hs closely related with Tc and Hc2, respectively, is reasonabl interpreted basically in terms of pronounced effects of superconducting fluctuations on the low temperature electrical transport properties. Further, (almost) saturated resistivity in steady field higher than Hs exhibits a singular -log T dependence over the wide range of temperatures. This is found just below the temperature where the positive magnetoresistance effect starts to be observed. We believe that these three empirical rules revealed in the present systems hold universally in superconducting amorphous metals with extreme homogeneity and with high resistivity. » weiterlesen» einklappen

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Klassifikation

DFG Fachgebiet:
Physik der kondensierten Materie

DDC Sachgruppe:
Physik