THEORETICAL STUDIES OF AN ABSORPTION SPECTRUM OF AN ANTIFERROMAGNETIC RARE-EARTH GARNET, DY3AL5O12

Crystal field calculations have been performed on the 6F3/2, 6F5/2, 6F7/2, 6H5/2 and 6H15/2 states of the Dy 3+ ion in the paramagnetic state. The optical absorption spectra for the transition 6H15/2 → 6F5/2 have also been studied in detail. The results indicate that the signs of some of the crystal field parameters Vnm based on a point charge calculation have to be changed in order to reproduce the observed level positions and g values of the 6F5/2 state. Such change of the crystal field parameters may be ascribed to large shielding of the crystal field potential. The selection rules derived in the present paper are consistent with the ones obtained in the preceding paper. The theoretical selection rules have been applied successfully to the splittings of the 6F 5/2 and 6H15/2 states below the Néel temperature by using the molecular field approximation. The magnetic-field effect on the absorption lines below the spin-flop field has also been discussed. © 1969, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.