Speaker
Description
The interaction between engineered defect structures and the superconducting flux line lattice plays an important role in determining the macroscopic electrodynamic properties of high-Tc cuprates. In this work, we investigate the effects of artificial pinning architectures in top-seeded melt-grown (TSMG) YBCO bulk superconductors. Micro-holes were introduced on the sample surfaces using ultrashort-pulsed (femtosecond) laser irradiation, a technique that operates with minimal microstructural damage typically associated with processing brittle ceramic materials on the order of less than 1 micron. Transport and magnetic measurements indicate that this surface modification alters the magnetic flux distribution and leads to an enhancement in the critical current density (Jc) and the levitation force. Isothermal magnetization (M-H) measurements show a more pronounced second magnetization peak (SMP) in the laser-processed samples compared to pristine ones. The observed enhancement in Jc (H) is discussed in terms of vortex dynamics and pinning, where the laser-induced mesoscopic defects are proposed to act as additional pinning centers, modifying the balance between different vortex creep regimes and possibly extending the stability of disordered vortex phases at higher magnetic fields. These results provide insight into the role of engineered defect landscapes in tuning vortex behavior and improving the performance of YBCO-based bulk superconductors for levitation applications. In addition, we have modelled a search for underlying mechanisms using COMSOL to calculate the mimicking structure resembling the samples used for experimental analysis reported in previously published research work [1]. A detailed comparison will be presented in view of numerically calculated findings of superconducting samples with artificial holes, the microstructure and superconducting properties therein reported.