We report on the magnetic properties of ${\mathrm{Eu}}_2{\mathrm{Ir}}_2{\mathrm{O}}_7$ 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 $T_N$, i.e., the critical transition temperature to the magnetic phase, on $P$. Strikingly, the recently calculated behavior for $T_N$ 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 ${\mathrm{Ir}}^{4+}$ 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-$\mathrm{in}/4$-out ground state across the accessed region of the phase diagram.

• Received 2 November 2015
• Revised 3 March 2016

DOI:https://doi.org/10.1103/PhysRevB.93.104422