Superconductor/ferromagnet heterostructures exhibit potential for significant reduction of hysteretic losses

TL;DR

This paper reports the first experimental demonstration of ferromagnetic shielding in high-Tc superconducting conductors, showing significant reduction in hysteretic AC losses, supported by finite-element simulations.

Contribution

It provides the first experimental evidence of ferromagnetic shielding effects in high-Tc superconductors and validates a finite-element model to predict loss reduction.

Findings

Ferromagnetic shields reduce AC hysteretic losses in superconductors.

Finite-element simulations accurately predict experimental results.

Potential for significant loss reduction using ferromagnetic materials.

Abstract

First experimental observations of the ferromagnetic shielding effect in high-Tc superconducting coated conductors were carried out. Experimental results were compared to simulations calling upon finite-element calculations based on the H-formulation of Maxwell equations to model superconducting strips with ferromagnetic shields. Samples of copper-stabilized coated conductors were electroplated with nickel shields and afterwards characterized. Both externally applied oscillating transverse magnetic fields as well as transport currents were studied. Having observed promising gains with respect to the reduction of ac losses in both cases, we further investigated the potential of ferromagnetic shielding. The numerical model was able to reproduce and also predict experimental results very well and will serve as an indispensable tool to determine the potential of soft ferromagnetic materials to significantly reduce hysteretic losses.