A polarized neutron reflectometry study of the spin glass freezing in a 29nm thick AuFe film

We performed polarized neutron reflectometry (PNR) experiments on a 29nm thick Au93Fe7 film in a temperature range from 295K down to 2K in a vertical magnetic field up to 6T. These high-field experiments were performed on the C5 spectrometer in Chalk River, Canada, using a split-pair cryomagnet. The magnetization as determined by PNR can be described with a Brillouin function from 295K down to 50K assuming the magnetic moment of isolated Fe atoms, i.e. 4muB per Fe atom. Below 50K the onset of the spin-glass freezing is observed as a strong deviation from this Brillouin type behavior of isolated atoms.