Double-Spin-Flip Resonance of Rhodium Nuclei at Positive and Negative Spin Temperatures

J. T. Tuoriniemi, T. A. Knuuttila, K. Lefmann, K. K. Nummila, W. Yao, F. B. Rasmussen
2000 Physical Review Letters  
Sensitive SQUID-NMR measurements were used to study the mutual interactions in the highly polarized nuclear-spin system of rhodium metal. The dipolar coupling gives rise to a weak double-spin-flip resonance. The observed frequency shifts allow deducing separately the dipolarlike contribution and the isotropic exchange term. For the first time, such measurements were extended to negative absolute temperatures as well. We find an effective dipolar moment 0.10m N of which about 15% is attributed
more » ... a conduction electron mediated pseudodipolar interaction. The isotropic exchange is described by R 20.9 6 0.1.
doi:10.1103/physrevlett.84.370 pmid:11015913 fatcat:4sv2u3qclzgc5o24yogjoaqy6e