An investigation of the magneto-optical properties of thin-film magnetic structures

This study reports on the performance of multilayer film structures, which are a very prospective material for thin-film magnetic sensors. The magnetic and magneto-optical properties of iron and cobalt thin films and also ferromagnetic (FM)/non-magnetic layer (NML)/FM trilayers, prepared using a magnetron sputtering system, are presented. The FM layer thickness of t_Fe and t_Co in trilayers varied from 25 to 100 Å and the NML thickness of t_NML varied from 5 to 2000 Å. In the NML/FM samples, the NML thickness varied from 0 to 400 Å. The dependences of the hysteresis characteristics of Fe films on the NML thickness were found. The dependence of the transverse Kerr effect (TKE) magnitude on t_Fe was established. It was shown experimentally that TKE is sensitive to the magnetization up to a certain depth range below the surface of ferromagnetic—the information depth. It was discovered that the in-plane hysteresis characteristic of the trilayers is strongly dependent on t_nml. So existence of the exchange coupling between FM layers through NML and its oscillatory behaviour (from antiferromagnetic (AF) to ferromagnetic (F) order) were experimentally established. It was found that the period AF–F–AF oscillations of exchange coupling is equal to 5–10 Å. (paper)