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University of Wollongong

2001

Superconductors

Articles 1 - 2 of 2

Full-Text Articles in Engineering

Vortex Matter In Superconductors, V M Pan, Alexey Pan Jan 2001

Vortex Matter In Superconductors, V M Pan, Alexey Pan

Australian Institute for Innovative Materials - Papers

The behavior of the ensemble of vortices in the Shubnikov phase in biaxially oriented films of the high-temperature superconductor YBa2Cu3O7−δ(YBCO) in an applied magnetic field is investigated for different orientations of the field. The techniques used are the recording of the current–voltage characteristics in the transport current and of resonance curves and damping of a mechanical oscillator during the passage of a transport current. It is shown that the behavior of the vortex ensemble in YBCOfilms, unlike the case of single crystals, is determined by the interaction of the vortices with linear defects—edge dislocations, …


Geometric Edge Barrier In The Shubnikov Phase Of Type Ii Superconductors, E Brandt Jan 2001

Geometric Edge Barrier In The Shubnikov Phase Of Type Ii Superconductors, E Brandt

Australian Institute for Innovative Materials - Papers

In type-II superconductors the magnetic response can be irreversible for two different reasons: vortex pinning and barriers to flux penetration. Even without bulk pinning and in the absence of a microscopic Bean–Livingston surface barrier for vortex penetration, superconductors of nonellipsoidal shape can exhibit a large geometric barrier for flux penetration. This edge barrier and the resulting irreversible magnetization loops and flux-density profiles are computed from continuum electrodynamics for superconductor strips and disks of constant thickness, both without and with bulk pinning. Expressions are given for the field of first flux entry Hen and for the reversibility field Hrev …