Comparison of small-field behaviour in MgB2, low and high temperature superconductors

Authors

Alexey V. Pan, University of WollongongFollow
S X. Dou, University of WollongongFollow

RIS ID

14211

Publication Details

Pan, AV & Dou, SX (2006), Comparison of small-field behaviour in MgB2, low and high temperature superconductors, Physical Review B (Condensed Matter and Materials Physics), 73(5), pp. 052506-1-052506-4.

Abstract

Different types of superconductors have been investigated at small magnetic fields (B_a) over wide temperature (T) ranges at different B_a orientations. It has been shown that the temperature dependence of the characteristic field (B*), separating the B_a-independent critical current density (J_c) plateau (single vortex pinning regime) and the region with J_c(B_a) (collective pinning), can be attributed either to the temperature dependence of the magnetic penetration depth for Nb-film and MgB₂bulk superconductors, or to thermally activated processes for Bi-based superconductors and YBa₂Cu₃O_7−δ superconducting films. In both cases the vortex pinning influence appears to have a secondary role, affecting the effective vortex depinning radius. An exception in such B*(T) behavior is considered for Nb film when the magnetic field has its considerable component applied perpendicular to the main surface of the film.