Size effects of optical and magneto-optical properties of epitaxial CrPt₃ films

The magneto-optical polar Kerr effect and the optical functions of epitaxial films of CrPt₃ have been studied as a function of film thickness. For this purpose, a wedge-shaped film was grown with film thickness ranging from 0 to 100 nm. A Kerr rotation of about 0.25° and -0.5° has been found in the near-ultraviolet and near-infrared spectral range, respectively, for the thicker films, decreasing rapidly with decreasing film thickness. In contrast, the shapes of the Kerr rotation and ellipticity spectra remain nearly unchanged. The optical functions are found to be strongly affected by the film morphology, which was studied by reflection high-energy electron diffraction and atomic force microscopy. The results are in good agreement with effective-medium calculations. © 2003 American Institute of Physics.