Phase-field simulation of vortex dynamics in superconducting thin films under sinusoidal stress modulation

Abstract

This study investigates the dynamic behavior of magnetic flux lines in superconducting thin films under sinusoidal stress modulation via a phase-field model that couples the time-dependent Ginzburg-Landau (TDGL) equations with elasticity theory. The effects of strain amplitude, loading frequency, and pinning configurations on vortex dynamics, critical current efficiency, and critical temperature are systematically analyzed. Simulations show that low-frequency stress modulation enhances vortex trapping efficiency and critical current through strong vortex-pinning interactions, whereas high-frequency stress modulation induces phase lag and reduces efficiency. Moderate strain amplifies pinning gradients and increases vortex density, while excessive strain disrupts lattice uniformity. Periodic pinning arrangements achieve the highest trapping efficiency compared to random or graded distributions, attributed to uniform potential fields. The synergy between stress modulation and pinning density is quantified, identifying an optimal frequency and pinning parameters to maximize efficiency. The study further reveals the synergistic effects of dynamic stress and pinning density, and proposes an optimal combination of frequency and pinning parameters, offering a new perspective for enhancing the stability of superconducting thin films under dynamic stress.