Crystal field and hyperfine effects in ErNi2B2C

Recently, neutron diffraction and Moessbauer experiments have been performed on tetragonal ErNi2B2C. From these experiments, lowest crystal field energy gap, g-values and hyperfine splitting of 166Er in the sample have been estimated. But no theoretical calculations have been done to explain these values. The present paper reports the results of detail crystal field (CF) calculation and effects of hyperfine interaction of 166Er in the solid state ErNi2B2C. The CF state are eight Kramers doublets of which ± 1/2 is the ground one having highly anisotropic g-values. The observed hyperfine splitting was also explained by considering 166Er in the ligand field environment. (author)