Photoinduced magnetic anisotropy in yttrium-iron ferrite garnet monocrystalline films

Variations of magnetic anisotropy under the effect of nonpolarized and linearly-polarized tight in Y3Fe5O12(2ΔH ∼ 0.6) and Y3Fe5O12:Si(2ΔH ∼ 30) epitaxial films grown on (111) Ga2Gd5O12 substrates are investigated. It is determined that cube anisotropy and uniaxial one practically do not change after the initial illumination in nominally pure specimens of YIFs. Increase of cubic anisotropy by ∼ 10 and reduction of uniaxial one by ∼ 30% from the original value are observed in specimens alloyed with silicon. Simultaneous effect of nonpolarized light and magnetization-photomagnetic annealing results in anisotropy at any direction in film plane with slight magnetization axis (SMA), parallel to vector M both in unalloyed and alloyed specimens. In silicon-free specimens under the effect of polarized light the SMA of the induced anisotropy is determined by polarization vector and does not depend on M direction. In silicon-alloyed specimen the SMA of the induced anisotropy is determined by the directions of magnetization vector and occurs parallel to M. System of kinetic equations of anisotropic centre occurence is suggested to describe the experimental results