A New Measurement System of the Surface Magneto-Optic Kerr Effect (SMOKE)

A new system for measuring the surface magneto-optical Kerr effect (SMOKE) has been developed. The combination of a polarization modulating method using electrical detection, and signal processing using a computer, provides a very high sensitivity of 10^¿4 degrees and a good signal-to-noise ratio. Moreover, electrical calibration using a Faraday cell makes it possible to measure the absolute value of a Kerr rotation angle of order 10^¿4 degrees. The SMOKE hysteresis of a two-atomic-plane layer of fcc-Co grown on a Cu (100) surface was successfully measured; its Kerr rotation angle is about 5×10^¿4 degrees.