A trapped field of 17.7 T in a stack of high temperature superconducting tape

TL;DR

This paper reports the creation of the strongest permanent magnet using stacked high temperature superconducting tapes, achieving a trapped field of 17.7 T at 8 K, with potential applications in superconducting motors.

Contribution

It introduces a novel hybrid stack design that significantly enhances trapped magnetic fields in HTS tape stacks, surpassing previous records.

Findings

Achieved a 17.7 T trapped field at 8 K.

Maintained 17.6 T at 14 K.

Largest trapped field reported for HTS tape stacks.

Abstract

High temperature superconducting (HTS) tape can be cut and stacked to generate large magnetic fields at cryogenic temperatures after inducing persistent currents in the superconducting layers. A field of 17.7 T was trapped between two stacks of HTS tape at 8 K with no external mechanical reinforcement. 17.6 T could be sustained when warming the stack up to 14 K. A new type of hybrid stack was used consisting of a 12 mm square insert stack embedded inside a larger 34.4 mm diameter stack made from different tape. The magnetic field generated is the largest for any trapped field magnet reported and 30% greater than previously achieved in a stack of HTS tapes. Such stacks are being considered for superconducting motors as rotor field poles where the cryogenic penalty is justified by the increased power to weight ratio. The sample reported can be considered the strongest permanent magnet ever created.