Photoinduced features of Y₃Fe₅ O₁₂ nanocrystalline films

We have studied the photoinduced effects in the nanocrystallized Y ₃Fe₅O₁₂ films deposited on the Gd ₃Ga₅O₁₂ <1 1 1> substrates. We have found for the first time substantial changes of the birefringence, two-photon absorption and circularly polarized absorption in different regimes of treatment of the nanocrystallized films. The explanations of the observed phenomena are suggested. The absorption spectra were modeled by the DFT based calculations of the electronic structure and density of states, which have revealed the well-pronounced differences between the densities of states of the tetra- and octahedrally coordinated iron ions. In addition, the crystal field calculations of the Fe³ energy levels at the octahedral and tetrahedral positions have been performed.