Comment on "Trapped flux in a small crystal of CaKFe$_4$As$_4$ at ambient pressure and in a diamond anvil pressure cell" by S. L. Bud'ko et al

TL;DR

This paper critically examines experimental results on trapped flux in a small superconductor sample, arguing that these findings do not conclusively prove superconductivity in high-pressure hydrides, challenging prior interpretations.

Contribution

The authors provide a critical commentary that questions the interpretation of trapped flux measurements as evidence of superconductivity in hydrides under pressure.

Findings

Supports the view that trapped flux measurements do not confirm superconductivity in hydrides

Highlights potential misinterpretations of experimental data in high-pressure superconductivity studies

Reinforces skepticism about claims of superconductivity in certain hydride samples

Abstract

In their paper arXiv:2405.08189, Supercond. Sci. Technol. 37 (2024) 065010 [1], Bud'ko et al. present experimental results for trapped magnetic flux for a tiny sample of a type II superconductor. The paper aims to provide evidence in support of the interpretation that similar measurements performed in samples of hydrogen-rich materials under high pressure by Minkov, Bud'ko and coauthors [2] are conclusive evidence [3] for superconductivity in hydrides under pressure. Here we point out that the new evidence presented by Bud'ko et al. [1] further supports our interpretation [4],[5] that the reported measurements of trapped flux on hydrides under pressure [2] are evidence that the samples are $not$ superconducting.