Magneto-optical indicator film (MOIF) microscopy of granular and layer structures (abstract)

Abstract

We report on the possibilities of application of magneto-optical indicator film (MOIF) technique for visualization and direct experimental study in real time of the magnetization processes and nondestructive characterization of the quality of magnetic thin granular films and multilayers. The technique utilizes a transparent indicator film, a Bi-substituted iron garnet with in-plane anisotropy, placed on the top of a sample. Polarized light passes through the indicator film and is reflected back by an Al underlayer. Magnetic stray fields with a component perpendicular to the film plane are observed through the magneto-optic Faraday effect created in the garnet film. An investigation of the magnetic moment distribution in granular single films and multilayers was carried out using this method. Some examples of magnetic stray field images of domain walls of different types obtained by MOIF technique and magnetic force microscopy are described. The experimental data are compared with theoretical estimations. The detailed information is obtained on the spin rotation processes as well as on the domain wall nucleation and motion during the remagnetization of these materials. Peculiarities of the magnetization reversal of multilayers with different types of exchange interlayer coupling have been revealed and discussed.