Paramagnetic Resonance of Yb+++ in Aluminum and Gallium Garnets

Abstract

The paramagnetic resonance spectrum of ${\mathrm{Yb}}^{\mathrm{+++}}$ in gallium and aluminum garnets has been observed at liquid nitrogen and helium temperatures. The components of the principal $g$ tensor are 2.85, 3.60, and 3.74 in gallium garnet, and 2.47, 3.78, and 3.87 in aluminum garnet. In aluminum garnet, for a range of $\mathrm{Yb}$ concentrations (relative to $\mathrm{Y}$ ) of from 2% to .1%, the line width varies linearly from 98 gauss to 20 gauss. The longitudinal relaxation time $T_1$ , for the same $\mathrm{Yb}$ variation, increases from 0.001 sec to 0.02 sec.