Inhaltszusammenfassung

Finely modulated (YBa2Cu3O7)nY/(PrBa2Cu3O7)nPr superlattices (SL) with sharp X-ray satellite lines (up to the fifth order) were prepared by sequential dc-sputtering. The high degree of structural order is also reflected in high superconducting critical temperatures Tc and critical current densities jc measured for SL with nY=1 for the first time. The angular dependence of the pinning force density, i.e. jcab(B,T,), and the resistive transitions (B,T,), where is the angle between the external...Finely modulated (YBa2Cu3O7)nY/(PrBa2Cu3O7)nPr superlattices (SL) with sharp X-ray satellite lines (up to the fifth order) were prepared by sequential dc-sputtering. The high degree of structural order is also reflected in high superconducting critical temperatures Tc and critical current densities jc measured for SL with nY=1 for the first time. The angular dependence of the pinning force density, i.e. jcab(B,T,), and the resistive transitions (B,T,), where is the angle between the external field and the -axis, show a strong enhancement of the intrinsic anisotropy due to the superlattice structure. For parallel to the CuO2-layers (B,T) and jc(B,T) of SL with nY?2 are nearly independent on the magnetic field. Since the superconducting order parameter is zero in the PrBa2Cu3O7 layers, we conclude that these SLs act like a stack of ultrathin superconducting film. Consequently, they exhibit a 2-dimensional behavior at low temperatures with jc(B,)=jc(Bcos,0°). » weiterlesen» einklappen

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DFG Fachgebiet:
Physik der kondensierten Materie

DDC Sachgruppe:
Physik