The Effect of Seed Distance on the Lateral Guidance Force of Multi-Seeded YBCO Superconductors

Abstract

High temperature superconductors (HTSs) have been widely used in magnetic bearing systems, magnetically levitated transportation systems (Maglev), superconducting motors, etc. due to their stable levitation properties. Although the studies on Maglev systems have been increasing in recent years, both the vertical levitation and lateral guidance forces are not at desired level for technological applicability of these systems. Furthermore, the studies have been mostly focused on enhancing the levitation force rather than the guidance force. One of the ways to improve the levitation and guidance forces of Maglev systems is improving the superconducting properties of HTSs and/or producing HTSs in larger single domains and in large geometries. The most effective method to produce HTSs in larger single domain within a reasonable production time is the multi‒seeded melt growth (MSMG) method. However, it can be seen from the studies in literature that the increasing seed number on HTSs corrupts the superconducting properties of MSMG samples. One can overcome this negation by changing the number, orientation and distance of the seeds. In this study, we have produced cylindrical YBCO superconducting samples with different distance of seeds by MSMG method and investigated the effect of seed distance on the lateral guidance force both in zero field cooling (ZFC) and field cooling (FC) regimes at different measurement temperatures of 77 K, 80 K and 83 K. The results showed that the movement stability of Maglev systems can be increased by changing the distance of the seeds in HTSs.