Enhanced Interfacial Magnetic Coupling of Gd<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>/</mml:mi></mml:math>Fe Multilayers

Abstract

The spatial extent ${\ensuremath{\zeta}}_{\mathrm{AFM}}$ and strength ${J}_{\mathrm{AFM}}$ of the antiferromagnetic (AFM) exchange coupling at buried Gd $/$Fe interfaces in ferrimagnetic $[\mathrm{Gd}(50\AA{})\mathrm{Fe}(15,35\phantom{\rule{0ex}{0ex}}\AA{}){]}_{15}$ sputtered multilayers is obtained from combined x-ray resonance magnetic reflectivity and magnetic circular dichroism measurements. ${\ensuremath{\zeta}}_{\mathrm{AFM}}$ is $4.1(7)\phantom{\rule{0ex}{0ex}}\AA{}$ or $\ensuremath{\sim}1--2$ interatomic distances in bulk Gd and Fe; ${J}_{\mathrm{AFM}}$ is 1050(90) K, comparable to the ferromagnetic exchange in bulk Fe.