Magnetic resonance determination of the antiferromagnetic coupling of Fe layers through Cr

Abstract
Variable frequency ferromagnetic resonance (FMR) has been used to directly observe the coupled resonance modes in single-crystal Fe/Cr/Fe(001) sandwiches grown by molecular-beam epitaxy. Magnetization M and magnetoresistance measurements also were carried out on these samples, which exhibited antiferromagnetic (AF) layer alignment for 12 Å(Cr)̊. The FMR data reveal two resonance modes with complex frequency dependences for the AF-aligned samples. The detailed FMR and M vs H behavior can be quantitatively explained by an AF coupling parameter J which has a thickness dependence peaked about t(Cr)=16 Å.