Magnetic field dependence of the magnetization of a 29 nm thick AuFe spin glass film

We performed polarized neutron reflectometry (PNR) experiments on a 29 nm thick Au93Fe7 film. The measurements were done in a temperature range from 300 K to 2 K in a magnetic field up to 6 T applied in the sample's plane, at 2 K we took PNR data up to 11 T. The magnetization as determined by PNR can be described with a Brillouin function from 295 K down to 50 K assuming the magnetic moment of isolated Fe atoms, i.e. 4 |μB per Fe atom. Below 50 K the onset of the spin-glass freezing was observed as a strong reduction of the magnetic moment compared to the isolated Fe atom.