Inhaltszusammenfassung

The anisotropic lower critical fields Hcc1(T) and Habc1(T) of polycrystalline YBa2Cu3O7, reported in this paper, consist of two separate parts which can be individually described by Hc1(T) = Hc1(0)(1?T2/T2cj with two critical temperatures Tc,u · 90 K and Tc,1 · 36 K. Substitution of Cu by Ni or Zn leads to monotonous reductions of these critical parameters. The experimental results closely resemble the Hc1(T) behaviour of the heavy-fermion system ( Th)Be13 which has been taken as evidence for...The anisotropic lower critical fields Hcc1(T) and Habc1(T) of polycrystalline YBa2Cu3O7, reported in this paper, consist of two separate parts which can be individually described by Hc1(T) = Hc1(0)(1?T2/T2cj with two critical temperatures Tc,u · 90 K and Tc,1 · 36 K. Substitution of Cu by Ni or Zn leads to monotonous reductions of these critical parameters. The experimental results closely resemble the Hc1(T) behaviour of the heavy-fermion system ( Th)Be13 which has been taken as evidence for a second phase transition. For Ce(Cu1?xRux)2Si2 experimental indications for two transitions into the superconducting state have been observed in xac(T) and specific heat data. » weiterlesen» einklappen

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Klassifikation

DFG Fachgebiet:
Physik der kondensierten Materie

DDC Sachgruppe:
Physik