Pulsed field magnetization of 0°–0° and 45°–45° bridge-seeded Y–Ba–Cu–O bulk superconductors. (14th October 2015)

• Record Type: Journal Article
• Authors: Ainslie, M D; Zou, J; Mochizuki, H; Fujishiro, H; Shi, Y-H; Dennis, A R; Cardwell, D A
• Is Part Of: Superconductor science & technology. Volume 28:Number 12(2015:Dec.)
• Publication Date: 2015-10-14
• Subjects: bulk superconductors -- multi-seeding -- bridge-shaped seeds -- trapped field magnets -- pulsed field magnetization -- numerical modelling -- finite element method (FEM) modelling; Superconductivity -- Periodicals; Superconductors -- Periodicals; 537.623
• DOI: 10.1088/0953-2048/28/12/125002
• Languages: English
• ISSNs: 0953-2048

Abstract

Abstract: Large, single-grain (RE)BCO (where RE = rare earth or Y) bulk superconductors with complicated geometries are required for a variety of potential applications, such as rotating machines, magnetic bearings and magnetic separation. As a consequence, the top multi-seeded melt growth process has been studied over many years in an attempt to deliver large, single grains for practical applications. Among these techniques, the so-called bridge-seeding produces the best alignment of two seeds during melt processing of multi-seed samples. In this paper, the trapped field performance and magnetic flux dynamics of two bridge-seeded, multi-seed samples magnetized by pulsed field magnetization are analyzed: one with a 45°–45° and another with a 0°–0° bridge seed. Based on an analysis of the flux penetration across the seeds and in-between the seeds of the 45°–45° multi-seed sample, an estimated J c distribution over the ab -plane is determined, which provides the basis for further analysis via numerical simulation. A three-dimensional finite-element model, developed to qualitatively reproduce and interpret the experimental results, was employed to investigate the influence of the length of the bridge seed for such multi-seed samples. The simulation results agree well with the observed experimental results, in that the multi-seed sample's particular inhomogeneous J c distribution acts to distort the trapped field profile from a traditional conical Bean's profile, which is determined by the length and direction of the bridge seed on the bulk surface.