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T. Mukai, Christoph Hufnagel, A. Kasper, T. Meno, A. Tsukada, K. Semba, F. Shimizu:
"Persistent Supercurrent Atom Chip";
Physical Review Letters, 98 (2007), 260407-1 - 260407.-4.

Rubidium-87 atoms are trapped in an Ioffe-Pritchard potential generated with a persistent supercurrent
that flows in a loop circuit patterned on a sapphire surface. The superconducting circuit is a closed loop
made of a 100 m wide molecular-beam epitaxy-grown MgB2 stripe carrying a supercurrent of 2.5 A. To
control the supercurrent in the stripe, an on-chip thermal switch operated by a focused argon-ion laser is
developed. The switch operates as an on/off switch of the supercurrent or as a device to set the current to a
specific value with the aid of an external magnetic field. The current can be set even without an external
source if the change is in the decreasing direction.