Apertureless scanning near-field magneto-optical microscopy of magnetic multilayers

We imaged magnetic domains in Pt/Co/Pt multilayers using an apertureless sc anning near-field optical microscope operating in reflection mode. As the m agneto-optical effects are weak for this kind of structure, a polarization modulation technique with a photoelastic modulator was used to reveal the c ontrast between magnetic domains. In the case of a Pt/Co/Pt trilayer struct ure, a strong improvement in lateral resolution is observed compared with f ar-field magneto-optical images and good sensitivity is achieved. In the ca se of a Pt/[Co/Pt]Pt multilayer structure, stripe domains of 200 nm width c ould be resolved, in good agreement with images obtained by magnetic force microscopy on the same structure.