Paramagnetic Resonance in Some Lanthanon Ethyl Sulphates

J. M. Baker, B. Bleaney

Abstract

Paramagnetic resonance in rare earth ions with an even number of unpaired 4f electrons is discussed with particular reference to experimental results in Pr$^{3+}$, Tb$^{3+}$ and Ho$^{3+}$ ions in single crystals of the ethyl sulphates. The crystal field theory of Elliott & Stevens is used to interpret the results. Some second-order perturbation mechanisms are considered which give rise to apparent quadrupole and hyperfine structure interactions. The following nuclear data are obtained from these experiments: $^{141}$Pr: I = $\frac{5}{2}$; $|\mu|$ = 3$\cdot$92 $\pm$ 0$\cdot$2 n.m.; $^{159}$Tb: I = $\frac{3}{2}$; $|\mu|$ = 1$\cdot$52 $\pm$ 0$\cdot$08 n.m.; $^{167}$Ho: I = $\frac{7}{2}$; $\mu$ = + 3$\cdot$29 $\pm$ 0$\cdot$17 n.m.; Q = + 0$\cdot$7 $\pm$ 0$\cdot$7 barm.