Electron spin-echo studies of hydrogen- and gadolinium-doped calcium fluoride

Investigation of relaxation phenomena using two-pulse and three-pulse electron spin-echo technique was carried out on hydrogen- and gadolinium-doped single-crystal calcium fluoride. Measurements were made on calcium-fluoride crystals singly doped with ${\mathrm{H}}^0$ and ${\mathrm{Gd}}^{3+}$ and doubly doped with both ${\mathrm{H}}^0$ as well as ${\mathrm{Gd}}^{3+}$. Echo decay functions and phase memory times were determined in the 1.2-2.2 °K temperature range. The results are interpreted using existing theories of electron spin-echo decay. A discussion of the results and of deviations from theories is presented. Three-pulse spin-echo decay measurements are also used to determine the spinlattice relaxation time of spins in the $\frac{5}{2}\leftrightarrow \frac{3}{2}{\mathrm{Gd}}^{3+}$ cubic line in Ca${\mathrm{F}}_2$.