Magnetic response of mesoscopic superconducting rings with two order parameters.
The magnetic response and fluxoid transitions of superconducting aluminum rings of various sizes, deposited under conditions likely to generate a layered structure, show good agreement with a two-order-parameter Ginzburg-Landau model. For intermediate couplings, we find metastable states that have different phase winding numbers around the ring in each of the two order parameters. Those states, previously theoretically predicted, are analogous to fractional vortices in singly connected samples with two-order-parameter superconductivity. Larger coupling locks the relative phase so that the two order parameters are only manifest in the temperature dependence of the response. With increasing proximitization, this signature gradually disappears.
Bluhm
Hendrik
H
Department of Physics and Applied Physics, Stanford University, Stanford, California 94305, USA. hendrikb@stanford.edu
Koshnick
Nicholas C
NC
Huber
Martin E
ME
Moler
Kathryn A
KA