Theoretical calculation of the optical properties of Y3Fe5O12

The electronic structure and the optical properties of Y3Fe5O12 crystal are calculated using the local spin density approximation + U approach. The intra-atomic correlation effect of the Fe 3d electrons is shown to be important in describing the insulating nature of the crystal. With a choice of the parameters U = 3.5 eV and J = 0.8 eV in the model Hamiltonian, a gap of 2.66 eV is obtained and a significant lowering of the occupied potion of the Fe 3d states is observed. The calculated optical absorption in the range 3-6 eV is from the bulk O 2p to the Fe 3d band states. The calculated spin magnetic moments are in good agreement with experiment. (C) 2001 American Institute of Physics.