上海科技大学知识管理系统

Abrikosov vortices trapped in superconducting circuits can reduce their operation margin and, in some cases, even lead to failure. Moats have been introduced to reduce the impact of Abrikosov vortices by providing a favorable location for trapping them at a distance from the circuit. However, the distribution mechanism of vortices near moats driven by applied magnetic fields and currents remains unclear. In this study, we used multiple moats to construct square-shaped areas in the niobium (Nb) thin film and employed magnetic force microscopy to observe the distribution of vortices induced by applied magnetic fields and currents near these areas. The moats effectively prevented vortices from entering the square-shaped area, particularly when the spacing between two moats was <550 nm. Furthermore, we discovered that the edges of moats generated new vortices with polarities opposite to those entering from both the edges of the Nb film under applied current. These vortices attracted each other and annihilated in pairs. These findings provide more insights into designing the layouts of superconducting integrated circuits.