Superhyperfine Structure of the EPR Spectra of Nd{sup 3+} Impurity Ions in Fluorite CaF{sub 2}

EPR spectra of a CaF{sub 2} single crystal that was grown from melt containing a small addition of NdF{sub 3} were studied. Signals corresponding to tetragonal centers of Nd{sup 3+} ions and cubic centers of Er3+ and Yb3+ ions were found. Superhyperfine structure (SHFS) in the spectra of the Nd{sup 3+} ions was observed for the first time in this crystal; parameters of the superhyperfine interaction of the Nd{sup 3+} ions with the nearest nine fluorine ions were determined. The dependence of the resolution of the Nd{sup 3+} EPR spectrum SHFS on the incident microwave power at the temperature of T ≈ 6 K was studied. Obtained results are discussed and compared with the literature data.