Comment on “Magnetic flux trapping in hydrogen-rich high-temperature superconductors” by V.S. Minkov, V. Ksenofontov, S.L. Bud’ko, E.F. Talantsev and M.I. Eremets, Nat. Phys. 19, 1293 (2023)

In the paper, Minkov et al. (2023), Eremets et al. present experimental results for flux creep measurements using H₃S under high pressure in a diamond anvil cell, the pioneering material for the era of hydride superconductivity, with the aim of providing evidence that magnetic flux is trapped in H₃S under high pressure and that persistent currents are circulating there. Initially, it was thought that the measurements started immediately after switching off the applied magnetic field, as indicated by the labeling of the horizontal axis of Fig. 4c of Ref. Minkov et al. (2023). However, it was revealed in private communications by Eremets et al. to the author and in a later paper by Bud’ko et al. (2024) [1] that there was a large delay time in starting the flux creep measurements. If that is the case, the measurement period of $10^4$ s or $10^5$ s as shown in Fig. 4c is too short to draw any conclusions about flux creep, or even to determine whether flux creep was being measured.