Photon pressure and magnetic moment transfer in multilayered nanosize films

The effect of nanosecond laser pulses with λ = 355 nm on the Kerr and Faraday angles in nanosize layered magnetic films Al₂O₃/TbFe/Al₂O₃/TbFe/Al₂O₃ and Al₂O₃/TbFe/Au/TbFe/Al₂O₃ is studied experimentally. The first ferrimagnetic TbFe layer in these films with transverse anisotropy is enriched by terbium, while the second Tb₂₂Fe₇₈ layer is enriched by iron relative to the composition at the compensation point. When the ferrimagnetic TbFe layers in the film are magnetized in the same direction, the magnetooptical characteristics of each TbFe layers and of the film as a whole depend on the laser radiation power, which is in good agreement with the temperature characteristics. When the TbFe layers are magnetized in opposite directions for a high power of nanosecond pulses, the values of the Faraday and Kerr angles for the output TbFe layer sharply change and even reverse their signs. These results are explained by the effect of electrons with a high spin polarization, which are injected by radiation due to the photon pressure. In the case of antiparallel magnetizations of the TbFe layers, a high concentration of such electrons not only changes the local magnetization of the output layer, but also causes its magnetization reversal due to magnetic moment transfer by such electrons.