Influence of hydrostatic pressure on the bulk magnetic properties of Eu2Ir2O7

We report on the magnetic properties of Eu2Ir2O7 upon the application of hydrostatic pressure P by means of macroscopic and local-probe techniques. In contrast to previously reported resistivity measurements, our dc magnetization data unambiguously demonstrate a nonmonotonic dependence of TN, i.e., the critical transition temperature to the magnetic phase, on P. Strikingly, the recently calculated behavior for TN closely reproduces our results under the assumption that P lowers the U/W ratio (i.e., Coulomb repulsion energy over electronic bandwidth). Zero-field muon-spin spectroscopy measurements confirm that the Ir4+ magnetic moment and/or the local magnetic configuration are only weakly perturbed by low P values. Accordingly, our current experimental findings strongly support the preservation of a 4-in/4-out ground state across the accessed region of the phase diagram.