EPR and optical studies ofγ-irradiated MgO: Ga

Abstract

EPR lines which appear when MgO: Ga is $\gamma$-irradiated at room temperature have been assigned to ${\mathrm{Ga}}^{2+}$ ions in substitutional cation sites. For ${}_{}{}^{69}{}_{}{}^{}\mathrm{Ga}$ at 77 K, we have $g=1.996\mathrm{}\pm 0.0005$ and $A=8.563\mathrm{}\pm 0.008$ GHz. Optical absorption bands at 370 and 300 nm in $\gamma$-irradiated MgO: Ga have been attributed to ${\mathrm{Ga}}^{2+}$ and ${\mathrm{Ga}}^{1+}$, respectively, as a result of bleaching and annealing experiments.