Photoinduced dynamic magnetic structure in FeBO3:Ni and its main properties

Main properties of the photoinduced dynamic structure in FeBO₃:Ni have been studied magneto-optically. The oscillations of the ferromagnetic moment are found to follow a quasiharmonic law. The deviation of the equilibrium direction of m in the structure from the direction of the applied magnetic field and the amplitude of its oscillations are found to decrease and the cyclic frequency of the oscillations to increase non-linearly, when the magnetic field applied along the wave vector of the structure during illumination is growing. The phase velocity of the photoinduced structure is found to increase linearly, when the intensity of the exciting illumination is growing. The discovered state of the magnetic system in FeBO₃:Ni is considered to be due to the Ni^III+ ions in the crystal and their interaction with photo-exited ions of the Fe³⁺ matrix.