TY - JOUR
T1 - Microwave response of vortices in superconducting thin films of Re and Al
AU - Song, C.
AU - Heitmann, T. W.
AU - Defeo, M. P.
AU - Yu, K.
AU - McDermott, R.
AU - Neeley, M.
AU - Martinis, John M.
AU - Plourde, B. L.T.
PY - 2009/5/1
Y1 - 2009/5/1
N2 - Vortices in superconductors driven at microwave frequencies exhibit a response related to the interplay between the vortex viscosity, pinning strength, and flux creep effects. At the same time, the trapping of vortices in superconducting microwave resonant circuits contributes excess loss and can result in substantial reductions in the quality factor. Thus, understanding the microwave vortex response in superconducting thin films is important for the design of such circuits, including superconducting qubits and photon detectors, which are typically operated in small, but nonzero, magnetic fields. By cooling in fields on the order of 100 μT and below, we have characterized the magnetic field and frequency dependence of the microwave response of a small density of vortices in resonators fabricated from thin films of Re and Al, which are common materials used in superconducting microwave circuits. Above a certain threshold cooling field, which is different for the Re and Al films, vortices become trapped in the resonators. Vortices in the Al resonators contribute greater loss and are influenced more strongly by flux creep effects than in the Re resonators. This different behavior can be described in the framework of a general vortex dynamics model.
AB - Vortices in superconductors driven at microwave frequencies exhibit a response related to the interplay between the vortex viscosity, pinning strength, and flux creep effects. At the same time, the trapping of vortices in superconducting microwave resonant circuits contributes excess loss and can result in substantial reductions in the quality factor. Thus, understanding the microwave vortex response in superconducting thin films is important for the design of such circuits, including superconducting qubits and photon detectors, which are typically operated in small, but nonzero, magnetic fields. By cooling in fields on the order of 100 μT and below, we have characterized the magnetic field and frequency dependence of the microwave response of a small density of vortices in resonators fabricated from thin films of Re and Al, which are common materials used in superconducting microwave circuits. Above a certain threshold cooling field, which is different for the Re and Al films, vortices become trapped in the resonators. Vortices in the Al resonators contribute greater loss and are influenced more strongly by flux creep effects than in the Re resonators. This different behavior can be described in the framework of a general vortex dynamics model.
UR - http://www.scopus.com/inward/record.url?scp=66749105238&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=66749105238&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.79.174512
DO - 10.1103/PhysRevB.79.174512
M3 - Article
AN - SCOPUS:66749105238
SN - 1098-0121
VL - 79
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 17
M1 - 174512
ER -