Paramagnetic Resonance Hyperfine Structure ofCe141andNd147

Abstract

The microwave paramagnetic resonance hyperfine structures of 33-day ${\mathrm{Ce}}^{141}$ and 11-day ${\mathrm{Nd}}^{147}$ have been observed in a single crystal of ${\mathrm{La}}_2$ ${\mathrm{Mg}}_3$ ${\left(\mathrm{N}{\mathrm{O}}_3\right)}_{12}$·24${\mathrm{H}}_2$O at 4.2°K. From the number of hfs lines we find directly the nuclear spins $I\left({\mathrm{Ce}}^{141}\right)=\frac{7}{2}$ and $I\left({\mathrm{Nd}}^{147}\right)=\frac{5}{2}$. The magnetic hyperfine coupling constants are found to be $B\left({\mathrm{Ce}}^{141}\right)=0.0126\mathrm{}\pm 0.0001$ ${\mathrm{cm}}^{-1\mathrm{}}$, and $B\left({\mathrm{Nd}}^{147}\right)=0.0237\mathrm{}\pm 0.0001$ ${\mathrm{cm}}^{-1\mathrm{}}$. From these the nuclear magnetic moments are calculated to be $\left|\mu \right({\mathrm{Ce}}^{141}\left)\right|=0.89\mathrm{}\pm 0.09$ nm, and $\left|\mu \right({\mathrm{Nd}}^{147}\left)\right|=0.542\mathrm{}\left|\mathrm{}\mu \right({\mathrm{Nd}}^{143}\left)\right|=0.56\mathrm{}\pm 0.06$ nm. These results are discussed in relation to those of the shell model and nuclear alignment experiments.