Vortex dynamics induced by scanning SQUID susceptometry

Published in Physical Review B, 2023

Citation: Logan Bishop-Van Horn*, Eli Mueller*, and Kathryn A. Moler, "Vortex dynamics induced by scanning SQUID susceptometry ", Phys. Rev. B 107, 224509 (2023). https://doi.org/10.1103/PhysRevB.107.224509

Publisher link: 10.1103/PhysRevB.107.224509

Open access link: arXiv:2304.13093

Associated GitHub resositories:

Vortex dynamics

Summary: We measured the local magnetic response of a niobium thin film by applying a millitesla-scale AC magnetic field using a micron-scale field coil and detecting the response with a micron-scale pickup loop in a scanning superconducting quantum interference device (SQUID) susceptometry measurement. Near the film’s critical temperature, we observed a step-like nonlinear and dissipative magnetic response due to the dynamics of a small number of vortex-antivortex pairs induced in the film by the local applied AC field. We modeled the dynamics of the measurement using a combined two-dimensional London-Maxwell and time-dependent Ginzburg-Landau approach, allowing us to construct a detailed real-space picture of the vortex motion causing the observed dissipative response. This work pushes scanning SQUID susceptometry of two-dimensional superconductors beyond the regime of linear response and lays the foundation for microscopic studies of vortex dynamics and pinning in superconducting devices and more exotic materials systems.