Superhyperfine Structure of the EPR Spectra of [Nd.sup.3+] Impurity Ions in Fluorite Ca[F.sub.2]

EPR spectra of a Ca[F.sub.2] single crystal that was grown from melt containing a small addition of Nd[F.sub.3] were studied. Signals corresponding to tetragonal centers of [Nd.sup.3+] ions and cubic centers of [Er.sup.3+] and [Yb.sup.3+] 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 [approximately equal to] 6 K was studied. Obtained results are discussed and compared with the literature data.