Resonant magnetic reflectivity in the extreme ultraviolet spectral range: Interlayer-coupled Co/Si/Ni/Fe multilayer system

Abstract

A polycrystalline test structure comprising a 5 nm cobalt and a 10 nm nickel/iron layer separated by a silicon layer ranging from 1.5 to 4 nm prepared by thermal evaporation has been investigated by resonant magnetic reflectivity measurements of horizontally polarized light in the extreme ultraviolet spectral range. By exploiting the transversal magneto-optical Kerr effect at the $M$ absorption edges of cobalt and nickel (59.5 eV and 66.5 eV) a magnetic contrast as large as 80% for cobalt and 25% for nickel can be obtained near a Brewster angle of about $45\ifmmode^\circ\else\textdegree\fi{}$. Angle- and energy-dependent scans of the magnetic asymmetry as well as element-selective, magneto-optical loops of the hysteresis were recorded against the thickness of the interlayer, reflecting the switching behavior of the individual ferromagnetic layers as a function of the interlayer coupling.