NUCLEAR MAGNETIC RESONANCE AND RELAXATION IN IRIDIUM METAL - NUCLEAR MAGNETIC DIPOLE MOMENTS OF 191IR AND 193IR

The nuclear magnetic resonances of Ir191 and Ir193 have been detected by pulsed NMR techniques in iridium metal in the temperature range T=1-4a°K and in external magnetic fields between 50 and 60 kOe. The observed frequency-field ratios for these isotropes are ν(191)H=0.074127(18) kHz/Oe and ν(193)H=0.080725(6) kHz/Oe. By combining the measured spin-lattice relaxation times T1(193)T=2.8±0.2 sec a°K with known values of the magnetic susceptibility and electronic specific heat, the Knight shift in iridium metal is estimated to be K=+(1.3±0.4)%. Applying this shift to the experimental frequency-field ratios yields the nuclear magnetic dipole moments (uncorrected for diamagnetic shifts) μ(191)=0.1440(6)μN and μ(193)=0.1568(6)μN. © 1968 The American Physical Society.