Onset of flux penetration into a thin superconducting film strip

Measurement of Critical Currents of Superconducting Aluminum Nanowires in External Magnetic Fields: Evidence for a Weber Blockade

“…The appearance of vortices in thin films of superconductors has been studied extensively, both theoretically [6,[20][21][22][23][24][25][26][27][28][29] and experimentally [3,[30][31][32]. In order to understand the observed oscillations of the critical current in magnetic field, we have to consider the characteristic dimensions of our samples.…”

Low-frequency flux noise in current-carrying high critical temperature superconducting films

“…It has been shown that electronbeam irradiation of YBCO crystals dramatically reduces the flux penetration field due to the effect of surface defects. 15 A theoretical study 16 on the surface barrier 17 of a strip film has also shown that the transverse penetration field decreases with increasing width of the edge defect layer relative to the effective penetration depth. At the edge of the beveled strip of sample III, a region of very small thickness d Ӷ L may exist, where L is the London penetration depth (about 200 nm) of YBCO.…”

“…After the current is removed, the magnetic field vanishes and the barrier reverts to a monotonous shape. 16,17 The flux vortices existing in the weak pinning region will then be swept out from the edge by thermal hopping, resulting in the disappearance of the flux noise. The role of the surface barrier in flux penetration at the film edge can also be inferred from previous studies on SQUIDs, where magnetic hysteresis has been reduced by improving the masking technology that ensured a steep edge.…”

Interaction of Abrikosov vortex with grain boundaries near Hc1. II. Magnetic and transport properties of polycrystalline high-Tc superconductors

“…Experiments show that the existence of Bean-Livingston surface barriers 7 as possible sources of hysteretic behavior. In the framework of the critical-state approach Kuznetsov et al 8 have estimated the enhancement of the magnetization of thin films with significant pinning owing to ''edge'' effects. Magnetization measurements by Zel'dova et al 9 revealed a new ''geometric barrier'' for thin films which significantly enhanced the potential barrier in the presence of a Bean-Livingston barrier.…”