Observation of the bulk spin-flop in an Fe/Cr superlattice

Abstract The layer magnetisation reorientation transition (spin-flop, SF) was studied in an artificial layer antiferromagnet (AF), namely in MgO(0 0 1)/[ 57 Fe(2.6 nm)/Cr(1.3 nm)] 20 epitaxial superlattice (SL) by synchrotron Mossbauer reflectometry and Kerr effect (SMOKE). The SF occurs simultaneously in the entire SL stack (bulk SF) in an increasing field of H SF =13 mT along the easy direction parallel to the layer magnetisations. It is recognised by the kink in the SMOKE loop and by the sharp up-rise of the AF Bragg peak in the delayed Mossbauer reflectivity. The moderate value of observed H SF is compared with estimations from a spin-chain model and interpreted as due to intraplane domain-wall motion during SF.