2 research outputs found
Continuous Melting of a "Partially Pinned" Two-Dimensional Vortex Lattice in a Square Array of Pinning Centers
The structure and equilibrium properties of a two-dimensional system of
superconducting vortices in a periodic pinning potential with square symmetry
are studied numerically. For a range of the strength of the pinning potential,
the low-temperature crystalline state exhibits only one of the two basic
periodicities (in the - and -directions) of the pinning potential. This
``partially pinned'' solid undergoes a continuous melting transition to a
weakly modulated liquid as the temperature is increased. A spin model,
constructed using symmetry arguments, is shown to reproduce the critical
behavior at this transition.Comment: 5 pages, 4 figure
London equation studies of thin-film superconductors with a triangular antidot lattice
We report on a study of vortex pinning in nanoscale antidot defect arrays in
the context of the London Theory. Using a wire network model, we discretize the
array with a fine mesh, thereby providing a detailed treatment of pinning
phenomena. The use of a fine grid has enabled us to examine both circular and
elongated defects, patterned in the form of a rhombus. The latter display
pinning characteristics superior to circular defects constructed with the
similar area. We calculate pinning potentials for defects containing zero and
single quanta, and we obtain a pinning phase diagram for the second matching
field, .Comment: 10 pages and 14 figure