Zeeman Effect of Cr3+ in ZnAl2O4

Abstract

The Zeeman effect for Cr3+ in the trigonally distorted octahedral site of ZnAl2O4 has been measured for applied fields up to 32 kOe. The lines whose splittings were observed correspond to the transitions E(Ē)2 and E(2Ā)→42A2(Ē) and A24(2Ā) (the R lines) in fluorescence. For H applied along the crystal [001] axis all four sites in the unit cell are equivalent and one of the upper-state g values is zero. Under these circumstances some of the observed lines correspond to a direct observation of the ground-state splittings in the nonlinear region of level crossing. The anisotropy of the upper and lower state g factors was determined from experiments in which the sample was rotated around a [110] direction with the magnetic field applied perpendicular to the rotation direction. The g values determined from the spectra are compared with calculated values from crystal-field theory given in the literature.