Ferromagnetic moments in metastable magnetic films by spin-polarized<i>–</i>neutron reflection

Abstract

We have used near-critical-angle reflection of polarized neutrons to probe for ferromagnetism in fcc Fe and Co epitaxial films (7 to 20 A\r{} thick). fcc Co on Cu(001) exhibits a strong ferromagnetic response with a magnetic moment per atom \ensuremath{\mu}=(1.8\ifmmode\pm\else\textpm\fi{}.25)${\mathrm{\ensuremath{\mu}}}_{\mathrm{B}}$. fcc Fe epitaxied to Cu(001) and Rh(001) shows no in-plane ferromagnetism in contrast to a polycrystalline bcc Fe film of similar thickness. The results are compared with the calculated magnitudes of local moments in these metastable magnetic phases.