Giant magnetic field induced effects in the second-harmonic generation in a planar anisotropic Ta/Co/Pt structure

Magnetic field induced effects in the second-harmonic generation in a thin asymmetric Ta/Co/Pt trilayer film with in-plane magnetic anisotropy are investigated. It is shown that the rotation of the polarization plane of the second-harmonic wave in the longitudinal magneto-optical Kerr effect configuration is as large as 37$^\circ$, which corresponds to a relative contribution from the magnetic field induced component of the second-harmonic field of about 30% and significantly exceeds the magnitude of the same effect for Co/Pt bilayer structures. It is shown that magnetization reversal in the Ta/Co/Pt structure occurs via the rotation of the magnetization vector within the film plane, and its direction is determined by the orientation of the easy magnetization axis of the structure relative to the applied field. The odd in magnetization contribution is experimentally observed in the intensity of the second harmonic in the longitudinal Kerr effect geometry, although it is forbidden by symmetry for the surfaces of uniformly magnetized structures.