Magnetic moment ofAg104mand the hyperfine magnetic field of Ag in Fe using nuclear magnetic resonance on oriented nuclei

Abstract

Nuclear magnetic resonance (NMR/ON) measurements with $\ensuremath{\beta}$- and $\ensuremath{\gamma}$-ray detection have been performed on oriented $^{104}\mathrm{Ag}$${}^{\mathit{g},\mathit{m}}$ nuclei with the NICOLE $^{3}\mathrm{He}$-$^{4}\mathrm{He}$ dilution refrigerator setup at ISOLDE/CERN. For $^{104}\mathrm{Ag}$${}^{\mathit{g}}$ (${I}^{\ensuremath{\pi}}={5}^{+}$) the $\ensuremath{\gamma}$-NMR/ON resonance signal was found at $\ensuremath{\nu}=266.70(5)$ MHz. Combining this result with the known magnetic moment for this isotope, the magnetic hyperfine field of Ag impurities in an Fe host at low temperature ($<1$ K) is found to be $|{\mathcal{B}}_{\mathrm{hf}}(\mathrm{Ag}\mathit{Fe})|=44.709(35)$ T. A detailed analysis of other relevant data available in the literature yields three more values for this hyperfine field. Averaging all four values yields a new and precise value for the hyperfine field of Ag in Fe; that is, $|{\mathcal{B}}_{\mathrm{hf}}(\mathrm{Ag}\mathit{Fe})|=44.692(30)$ T. For $^{104}\mathrm{Ag}$${}^{\mathit{m}}$ (${I}^{\ensuremath{\pi}}={2}^{+}$), the anisotropy of the $\ensuremath{\beta}$ particles provided the NMR/ON resonance signal at $\ensuremath{\nu}=627.7(4)$ MHz. Using the new value for the hyperfine field of Ag in Fe, this frequency corresponds to the magnetic moment $\ensuremath{\mu}(^{104m}\mathrm{Ag})=+3.691(3)$ ${\ensuremath{\mu}}_{\mathrm{N}}$, which is significantly more precise than previous results. The magnetic moments of the even-A $^{102\ensuremath{-}110}\mathrm{Ag}$ isotopes are discussed in view of the competition between the $(\ensuremath{\pi}{g}_{9/2}){}_{7/{2}^{+}}^{\ensuremath{-}3}(\ensuremath{\nu}{d}_{5/2}\ensuremath{\nu}{g}_{7/2}){}_{5/{2}^{+}}$ and the $(\ensuremath{\pi}{g}_{9/2}){}_{9/{2}^{+}}^{\ensuremath{-}3}(\ensuremath{\nu}{d}_{5/2}\ensuremath{\nu}{g}_{7/2}){}_{5/{2}^{+}}$ configurations. The magnetic moments of the ground and isomeric states of $^{104}\mathrm{Ag}$ can be explained by an almost complete mixing of these two configurations.