Inhaltszusammenfassung

Thin amorphous films of superconducting (Mo0.6Ru0.4)1?xBx were prepared by magnetron sputtering in an ultrahigh vacuum (UHV) system. The superconducting properties and normal state resistivities ? of films condensed at 77 K are discussed. We find a strong dependence on the sputter conditions of the low?temperature resistivity ?LT =? (25 K) and its variation upon irradiation with 20?MeV sulphur ions, although the superconducting critical temperature Tc and the temperature dependence of ? are n...Thin amorphous films of superconducting (Mo0.6Ru0.4)1?xBx were prepared by magnetron sputtering in an ultrahigh vacuum (UHV) system. The superconducting properties and normal state resistivities ? of films condensed at 77 K are discussed. We find a strong dependence on the sputter conditions of the low?temperature resistivity ?LT =? (25 K) and its variation upon irradiation with 20?MeV sulphur ions, although the superconducting critical temperature Tc and the temperature dependence of ? are not strongly influenced for all films prepared. Whereas films sputtered with argon pressures below ?10?2 mbar have resistivities of about 100 ???cm which are reduced 2?3% by irradiation, films sputtered with higher argon pressures have resistivities up to 1000 ???cm and show irradiation?induced decreases of almost 70%. Independent of this behavior, the x?ray diffraction patterns appear nearly identical, and Tc increases 6?10% with irradiation. Assuming that irradiation defects reduce the structural short?range order, the effects observed with low?resistance films could be explained by a smearing of the structure factor S(k) and an enhancement of the electronic density of states at the Fermi level N(EF). Our results suggest that the structure of high?resistance films has initially a reduced density which is increased by irradiation.» weiterlesen» einklappen

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Klassifikation

DFG Fachgebiet:
Physik der kondensierten Materie

DDC Sachgruppe:
Physik