Dielectric tensor for interfaces and individual layers in magnetic multilayer structures

The magneto-optical Kerr response of metallic magnetic multilayers has been studied by determining the dielectric tensors (dielectric functions) for i ndividual layers, including the magnetic and nonmagnetic interfacial layers . The diagonal components of these tensors were determined using in situ el lipsometric analysis, where the ellipsometric data were taken in real time during multilayer deposition. The off-diagonal components were determined b y regression fitting magneto-optic polar Kerr rotation and ellipticity data to models supported by electromagnetic theory. The Voigt parameters (ratio between off-diagonal and diagonal components of dielectric tensors) were d etermined from these model fits. Higher magnitudes for the Voigt parameters were found at interfaces, corresponding with stronger Kerr responses obser ved in those materials. Five different magnetic multilayer systems were stu died, including Pt/Co, Pd/Co, Au/Co, Cu/Co, and Pt/Fe multilayer structures . The Voigt parameters for the magnetic layers and magnetic-nonmagnetic int erfaces in all five structures were determined, and in turn the dielectric tensors for the respective layers were also determined. (C) 2000 American I nstitute of Physics. [S0021-8979(00)05317-2].