Trapping a magnetic field of 14.8 T using stacked coated conductors of 12 mm width

TL;DR

This study demonstrates the fabrication and characterization of a compact, stacked coated conductor magnet capable of trapping a magnetic field of 14.8 T at 10 K, with insights into flux penetration effects.

Contribution

It introduces a novel stacked coated conductor design for high-field trapping and provides a detailed analysis of flux penetration phenomena affecting trapped field performance.

Findings

Achieved a maximum trapped field of 14.8 T at 10 K.

Faster field ramp rates are effective at higher temperatures.

Discrepancy between calculated and experimental trapped fields explained by flux jets.

Abstract

We fabricated a compact (13$\times$12$\times$12.5 mm${^3}$) trapped-field magnet by stacking 200 pieces of EuBa${_2}$Cu${_3}$O${_7}$ coated conductors with BaHfO${_3}$ nanorods as artificial pinning centers. It was magnetized by field-cooling method using a 18 T superconducting magnet, and the maximum field of 14.8 T was trapped at 10 K at a field-ramp rate of 0.1 T/min. At higher temperatures, although the trapped field was decreased, we could trap the field with much faster ramp rate. In order to understand these results, we also performed calculations of the trapped field based on $J_\mathrm{c}-H$ characteristics of the coated conductor. The calculated trapped field value was larger than the experimental value at 10 K. This discrepancy can be understood by considering the reduction of the effective size of the stacked coated conductors due to the existence of extended regions of irregular flux penetration called "flux jets".