Vortex 'puddles' and magic vortex numbers in mesoscopic superconducting disks
The magnetic properties of a superconducting disk change dramatically when its dimensions become mesoscopic. Unlike large disks, where the screening currents induced by an applied magnetic field are strong enough to force vortices to accumulate in a 'puddle' at the centre, in a mesoscopic disk the interaction between one of these vortices and the edge currents can be comparable to the intervortex repulsion, resulting in a destruction of the ordered triangular vortex lattice structure at the centre. Vortices instead form clusters which adopt polygonal and shell-like structures which exhibit magic number states similar to those of charged particles in a confining potential, and electrons in artificial atoms. We have fabricated mesoscopic high temperature superconducting Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+δ} disks and investigated their magnetic properties using magneto-optical imaging (MOI) and high resolution scanning Hall probe microscopy (SHPM). The temperature dependence of the vortex penetration field measured using MOI is in excellent agreement with models of the thermal excitation of pancake vortices over edge barriers. The growth of the central vortex puddle has been directly imaged using SHPM and magic vortex numbers showing higher stability have been correlated with abrupt jumps in the measured local magnetisation curves.
- Research Organization:
- Ames Lab., Ames, IA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC02-07CH11358
- OSTI ID:
- 1025743
- Report Number(s):
- IS-J 7619
- Journal Information:
- Journal of Physics: Conference Series, Vol. 150, Issue 5; Conference: 25TH INTERNATIONAL CONFERENCE ON LOW TEMPERATURE PHYSICS (LT25) 6–13 August 2008, Amsterdam, The Netherlands. Part 5, Superconductivity
- Country of Publication:
- United States
- Language:
- English
Similar Records
Geometry-dependent penetration fields in superconducting Bi2Sr2CaCu2O8+δ platelets
Geometry-dependent penetration fields of superconducting Bi2Sr2CaCu2O8+δ platelets