Microstructure and trapped field of YBCO bulk single-grain superconductors prepared by interior seeding

Abstract

The microstructural analyses of YBCO bulk single-grain superconductors grown by interior seeding with taller and shorter upper pellets have shown that a suitable upper pellet height can lower the porosity in the upper part of the sample, produce a more appropriate distribution of pinning centres in the form of Y-211 particles and suppress subgrain formation with a higher crystal misalignment in the c-growth sector (c-GS), which can lead to a higher measured trapped magnetic field and a more uniform cone of the trapped-field profile. The observed bulging of the sample surface at the c-GS can be explained by the edge melt distribution model, which shows that macroscopic mass transport to the growth sector occurs with higher growth rates.

Properties and Types of Superconductors

“…On the other hand, the investigations for a-axis growth rate trend are mostly attained through the upper most surface of compounds (Ras). Few researchers have done work on inner growth rate (Rai) and growth rate of surfaces (Rcs) [98]. Efficient growth rate investigation neither depends on the a-axis, c-axis directions, surface or internal, the foremost important thing is crystal structure growth procedure of YBCO [99].…”

A novel interior seed addition to improve the levitation force and the trapped field of multi-seeded YBCO bulk superconductors

“…In this work, we have proposed an Inner-Top Multiple-Seeding (IT-MS) method with reasonable combination of the interior and top seeding technique [25,26], so that we can design and optimize the shapes and space configurations of the single domain REBCO grains, as well as enhance the mechanical strength of multi-seeded REBCO bulk superconductors. At the same time, we have fabricated a rectangular shaped YBCO samples (geometric dimensions are 60 × 20 × 13 mm 3 ) using the multi-seeded technique (TMS) and IT-MS method.…”