  In an extension of our previous work, [Sergey L Bud'ko et al 2023 Supercond.
Sci. Technol. 36 115001] the measurements of temperature dependent
magnetization associated with trapped magnetic flux in a small single crystal
of CaKFe$_4$As$_4$, using zero-field-cooled and field-cooled protocols were
performed, on the same crystal, at ambient pressure without a pressure cell and
at 2.2 GPa in a commercial diamond anvil cell (DAC), showing comparable
results. The data show that with a proper care and understanding, trapped flux
measurements in superconductors indeed can be performed on samples in DACs
under pressure, as was done on superhydrides [V S Minkov et al 2023 Nat. Phys.
19 1293].
