Pressure dependence of the magnetization of URu2Si2

The ground state of URu2Si2 changes from so-called hidden order (HO) to large-moment antiferromagnetism (LMAF) upon applying hydrostatic pressure in excess of similar to 14 kbar. We report the dc magnetization M(B,T,p) of URu2Si2 for magnetic fields B up to 12 T, temperatures T in the range 2-100 K, and pressure p up to 17 kbar. Remarkably, characteristic scales such as the coherence temperature T-*, the transition temperature T-0, and the anisotropy in the magnetization depend only weakly on the applied pressure. However, the discontinuity in partial derivative M/partial derivative T at T-0, which measures the magnetocaloric effect, decreases nearly 50% upon applying 17 kbar for M and B parallel to the tetragonal c axis, while it increases 15-fold for the a axis. Our findings suggest that the HO and LMAF phases have an astonishing degree of similarity in their physical properties, but a key difference is the magnetocaloric effect near T-0 in the basal plane.