NMR and NQR studies of URu2Si2 and isostructural nonmagnetic references

The non-f compound ThRu2Si2 has been studied as an isostructural nonmagnetic reference for URu2Si2 using nuclear magnetic resonance (NMR) measurement. The temperature dependences of Knight shifts measured by Si-29-NMR and 99 Ru-NMR are independent of temperature. The results are consistent with data previously reported on the susceptibility. Ru-101-NQR frequency 101(nu Q) was also estimated from the 99 Ru-NMR measurement. 101(nu Q) of ThRu2Si2 is close to that of URu2Si2, especially at high temperatures, suggesting that U ions in URu2Si2 are in a nearly tetravalent state.