“…In some reports, the pressure medium was not disclosed [9,10,13,18,23,29,31,40,30]. It is remarkable that through the recent development of the T − P phase diagram of URu 2 Si 2 , one fact has remained mostly overlooked: the pressure studies upon which the phase diagram are based are almost exclusively performed using a 1:1 mixture of Fluorinert FC70 and FC77 that is hydrostatic only below a modest pressure.…”