Flux-trapping experiments on ultra-high pressure hydrides as evidence of superconductivity

Flux-trapping magnetization studies on H3S at ultra-high pressure have been reported by Minkov et al. as definitive evidence of superconductivity in this hydride system. This is very helpful in a field that has become somewhat controversial. However, this conclusion has been questioned based on an apparent zero-field cooled (ZFC) linear magnetization at low field. The standard Bean model would require an approximately quadratic dependence. In support, we note that the reported ZFC magnetization is indeed super-linear and consistent both with model calculations for thin discs and with the ZFC magnetization reported for YBa2Cu3Oy films. We conclude that the reported high-pressure magnetization data is fully consistent with superconductivity and that there is no reason, in this particular data set, to reject the original inference of hydride superconductivity.