Magneto-Optic Microscopy

Optical microscopy using the magneto-optic Kerr effect is a well established tool for imaging magnetic microstructure. We have built a microscope specifically for examining the thin film magnetic multilayers that we grow for our SEMPA studies of oscillatory exchange coupling.

This figure shows a schematic of the microscope. For good thin film sensitivity a design using a large (90°) scattering angle is used. We overcome the resulting depth of field problem by using a confocal imaging scheme in which a slit aperture only allows the focused part of the image through to the camera. To form a complete image the microscope focus and the slit are synchronously scanned. This method also provides the large field of view required to look at one of our multilayer wedge samples. As usual in Kerr microscopy the saturated magnetic state is used as a reference for removing topographic features as shown in these images from a NiFe thin film.

Online: May 1996
Last Updated: November 2007

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