Magnetic Field-Induced Second Harmonic Generation in Thin Films with Ferromagnet/Antiferromagnet Interfaces

We report on the experimental investigations of the optical second harmonic generation and magnetooptical effects at the second-harmonic frequency in thin films consisting of ferromagnetic and antiferromagnetic materials and including exchange-coupled layers, one of which is pinned with an antiferromagnetic layer. The exchange coupling manifests itself in such structures as a shift of the hysteresis loops relative to the zero magnetic field under the linear magnetooptical Kerr effect. We show that this effect appears to a much less extent in the nonlinear magnetooptical Kerr effect at the second harmonic response. The magnetic field dependences of the second harmonic intensity contain a single magnetic hysteresis loop slightly shifted relative to the zero magnetic field and this shift increases with a decrease in the laser pumping radiation power.