High upper critical field (120 T) with small anisotropy of highly hydrogen-substituted SmFeAsO epitaxial film

TL;DR

This study reports a highly hydrogen-substituted SmFeAsO epitaxial film with an extremely high upper critical magnetic field of 120 T and low anisotropy, indicating its potential for superconducting applications.

Contribution

The paper demonstrates the synthesis and characterization of a hydrogen-substituted SmFeAsO film with unprecedented upper critical field and low anisotropy, advancing understanding of its superconducting properties.

Findings

Upper critical field ({}Hc2) of 120 T at 2.2 K for {}H || ab.

Anisotropic parameter ({}) around Tc is approximately 2.

High hydrogen incorporation leads to small anisotropy and high critical fields.

Abstract

The electronic transport properties of a highly hydrogen-substituted 1111-type SmFeAsO epitaxial film with high critical-temperature (Tc = 45 K) were investigated under high magnetic fields. By using a single-turn magnet generating up to 130 T, we clarified that the upper critical field ({\mu}0Hc2) of SmFeAsO0.65H0.35 is 120 T at the nearly low-temperature limit of 2.2 K for {\mu}0H || ab. The angular dependence of {\mu}0Hc2 revealed that the anisotropic parameter ({\gamma}) around Tc is ~2, which is comparable with that of a practical candidate 122-type BaFe2As2 with lower Tc and much smaller than that of F-substituted SmFeAsO. The small {\gamma} mainly originates from the high hydrogen incorporation. The extremely high {\mu}0Hc2 and small {\gamma}, together with the high Tc and high critical current density, suggest that SmFeAsO1-xHx has high potential for the superconducting electromagnets and cables.