Development of a Hybrid Atomic Force and Scanning Magneto-Optic Kerr Effect Microscope for Investigation of Magnetic Domains

Abstract

We present the development of a far-field magneto-optical Kerr effect microscope.An inverted optical microscope was constructed to accommodate Kerr imaging and atomic force microscopy. In Kerr microscopy, magnetic structure is investigated by measuring the polarization rotation of light reflected from a sample in the presence of a magnetic field. Atomic force microscopy makes use of a probe which is scanned over a sample surface to map the topography. The design was created virtually in SolidWorks, a three-dimensional computer-aided drafting environment, to ensure compatibility and function of the various components, both commercial and custommachined, required for the operation of this instrument. The various aspects of the microscope are controlled by custom circuitry and a field programmable gate array data acquisition card at the direction of the control code written in National Instrument LabVIEW. The microscope has proven effective for both Kerr and atomic force microscopy. Kerr images are presented which reveal the bit structure of magnetooptical disks, as are atomic force micrographs of an AFM calibration grid. Also discussed is the future direction of this project, which entails improving the resolution of the instrument beyond the diffraction limit through near-field optical techniques.Preliminary work on fiber probe designs is presented along with probe fabrication work and the system modifications necessary to utilize such probes.i Acknowledgments I wish to thank the members of the Sánchez Nano-Development Lab in the physics department of Portland State University. This work could not have been successful without their continued advice and support. These include undergraduate research students