Reversible ratchet effects in a narrow superconducting ring

We study the ratchet effect in a narrow pinning-free superconductive ring based on time-dependent Ginzburg-Landau (TDGL) equations. Voltage responses to external dc an ac currents at various magnetic fields are studied. Due asymmetric barriers for flux penetration and exit ring-shaped superconductor, critical current above which flux-flow state is reached, as well transition normal state, different two directions of applied current. These effects cooperatively cause signal reversal high fields, has not been reported date system. The found here larger than those induced by pinning potentials. Our results also demonstrate feasibility using mesoscopic superconductors employ superconducting diode versatile devices.