https://doi.org/10.1140/epjb/e2011-20574-2
Regular Article
Superconducting state evolution with applied magnetic flux in mesoscopic rings
Department of Physics, Shanghai University,
Shanghai
200444, P.R.
China
a e-mail: zgq1981@shu.edu.cn
Received:
15
July
2011
Received in final form:
28
September
2011
Published online:
21
November
2011
The magnetic flux dependence of the vortex state for small mesoscopic superconducting rings surrounded by a medium is investigated by the phenomenological Ginzburg-Landau theory. The influences of the ring size and the surface superconductivity on the free energy and total supercurrent are studied. For narrow rings, the persistent current evolves towards a periodic behaviour with magnetic flux. The complete paramagnetic or diamagnetic state, corresponding to positive or negative current flowing in the whole ring, can occur. A remarkable intermittent superconducting behaviour for the ground-state transition is found when the strength of surface-suppressed superconductivity is enlarged or the ring size is decreased. Consequently, a pure superconducting state with positive total current can be obtained.
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2011
