Investigation of magnetic levitation performance in Ag-added DyBa2Cu3O7-δ superconductors fabricated by single-direction melt growth (SDMG) method

Abstract This study investigates the magnetic levitation and guidance characteristics of Ag-doped DyBa2Cu3O7-δ superconducting bulks, synthesized by the single-direction melt growth (SDMG) technique. The levitation force, vertical stiffness and lateral guidance force are measured at varying cooling heights (CHs) of 5 mm, 25 mm and 50 mm, with a constant working height (WH) of 5 mm for lateral force measurements. DyBa2Cu3O7-δ samples are cooled using liquid nitrogen (77 K) and thermal stabilization is achieved before force data collection. Results show that levitation forces increase with CH, while the levitation force curves exhibit both attractive and repulsive behavior depending on the CH. The lateral guidance force is higher for the Ag2 sample than for the Ag1 sample and decreased as the temperature decreased. Vertical stiffness also increased with CH and decreased as the levitation gap decreased, confirming heightened guidance forces at smaller distances. The flux density distributions, including both lateral ( B x ) and vertical ( B y ) components, are found to significantly impact the levitation and guidance force performance. Specifically, configurations with concentrated B x gradients improved levitation stability, while configurations with distributed B y led to stronger guidance forces. These findings underscore the importance of optimizing the PMG design to balance B x for levitation and B y for guidance in superconducting systems.