The hidden order phase in $\mathrm{U}{\mathrm{Ru}}_2{\mathrm{Si}}_2$ is highly sensitive to electronic doping. A special interest in silicon-to-phosphorus substitution is due to the fact that it may allow one, in part, to isolate the effects of tuning the chemical potential from the complexity of the correlated $f$ and $d$ electronic states. We investigate the new antiferromagnetic phase that is induced in $\mathrm{U}{\mathrm{Ru}}_2{\mathrm{Si}}_{2-x}{\mathrm{P}}_x$ at $x\gtrsim 0.27$. Time-of-flight neutron diffraction of a single crystal ($x=0.28$) reveals $c$-axis collinear ${\mathbf{q}}_{\mathrm{m}}=(\frac{1}{2},\frac{1}{2},\frac{1}{2})$ magnetic order with localized magnetic moments ($\sim 2.1$–$2.6{\mu }_{\mathrm{B}}$). This points to an unexpected analogy between the (Si,P) and (Ru,Rh) substitution series. Through further comparisons with other tuning studies of ${\mathrm{URu}}_2{\mathrm{Si}}_2$, we are able to delineate the mechanisms by which silicon-to-phosphorus substitution affects the system. In particular, both the localization of itinerant $5f$ electrons as well as the choice of ${\mathbf{q}}_m$ appear to be consequences of the increase in chemical potential. Further, enhanced exchange interactions are induced by chemical pressure and lead to magnetic order, in which an increase in interlayer spacing may play a special role.

• Received 3 February 2021
• Revised 16 May 2021
• Accepted 17 May 2021

DOI:https://doi.org/10.1103/PhysRevB.103.214403