Method to measure spectra of both the magneto-optical Kerr and the Faraday effect

Details of an integrated apparatus to measure spectra of both the magneto-optical Kerr and the Faraday effect by the use of a rotating analyzer are given. The absolute values of both the Kerr rotation angle theta(k) and the ellipticity epsilon(k) can be determined by means of an achromatic quarter-wavelength retarder. The system is simple and reliable, and fully controlled by a computer. The measured values of the Kerr and Faraday effects for one MnBi(Al) film sample and for one GaP crystal sample are given. Since the magnitude of the Faraday rotation signal is proportional to the sample thickness, one must be careful in determining the fundamental energy gap by use of the Faraday spectrum only. Employment of the Fourier-transform technique will enable the system to measure both the Kerr and the Faraday effect in a wider data range from one-hundredth to a few hundred degrees. (C) 1997 Society of Photo-Optical Instrumentation Engineers.