Temperature Dependence of the Hyperfine-Structure Splitting of Divalent Manganese in Single-Crystal Magnesium Oxide

The hyperfine-structure splitting of divalent manganese in single-crystal magnesium oxide has been reinvestigated. In the temperature range $T=4.2\mathrm{} \mathrm{to} 100$ K, it is found that the relative variation of hyperfine-structure splitting vs temperature follows a simple power law, where the exponent is given by $n=3.75\mathrm{}\pm 0.40$ and the constant of proportionality is reasonably close to that predicted by Simanek and Huang.