CEMS characterisation of Fe/high-κ oxide interfaces

The interfaces between Fe and different high-κ oxides are investigated by means of conversion electron Mössbauer spectroscopy (CEMS). Information on the magnetic ordering at the interface is obtained from the magnetic hyperfine splitting of the Mössbauer spectra. The reactivity of the Fe atoms at the interface (intermixing) is also estimated by CEMS. X-ray diffraction (XRD) and X-ray reflectivity (XRR) provide additional information on the intermixing and different phases present at the interface. CEM-spectra show the presence of both ferromagnetic and paramagnetic phases. CEMS and XRD results show that the Fe/HfO₂ and Fe/Al₂O₃ interfaces are the least reactive. The degree of intermixing between Fe and the high-κ oxide is determined by the oxide surface roughness.