ESR evidence of octahedral site occupation in ScHx:Er

Abstract

The Er³⁺ electron spin resonance spectrum at low temperatures in powdered Sc_.9988Er_.0012H_1.91 contains a Γ₇ doublet and associated hyperfine components with cubic site symmetry plus four additional resonances arising from two distinct transitions with axial site symmetry. The axial lines are attributed to octahedral site occupation by protons in the vicinity of some Er³⁺ impurities. The two axial transitions may be associated with two different types of distortions of the Γ₇ wave functions or possibly a Γ₈⁽¹⁾ quartet ground state.