NMR investigation of antiferromagnetism and coherence in URu2Si2−xPx

We report P31 and Si29 NMR in single crystals of URu2Si2−xPx for x=0.09 and x=0.33. The spectra in the x=0.33 sample are consistent with a homogenous commensurate antiferromagnetic phase below TN∼37 K. The Knight shift exhibits an anomaly at the coherence temperature T* that is slightly enhanced with P doping. Spin-lattice-relaxation rate data indicate that the density of states is suppressed for x=0.09 below 30 K, similar to the undoped compound, but there is no evidence of long-range order at this concentration. Our results suggest that Si substitution provides chemical pressure and electronic tuning mediated by filling of the s/p shells with minimal electronic inhomogeneity.