X-ray absorption spectroscopy and x-ray magnetic circular dichroism have been applied to study the oxidation reactions at the buried interface resulting from NiO deposition on Fe(001). The NiO layer is obtained by reactive deposition; i.e., by evaporating Ni in an O2 atmosphere. We find that NiO reactive deposition on Fe(001) promotes Fe oxidation, leading to the formation of a thick, oxygen-rich oxide, identified as Fe3O4. This ferrimagnetic interface oxide shows a net magnetization that couples ferromagnetically to the iron substrate. This behavior is different from the case of the Fe/NiO(001) interface, where formation of (antiferromagnetic) FeO occurs. A sample annealing following the growth of the NiO/Fe interface is found to reduce the iron and to induce Ni diffusion in the Fe substrate.
Chemical effects at the buried NiO/Fe(001) interface
M Finazzi;G Ghiringhelli;M Zacchigna;M Zangrando
2004
Abstract
X-ray absorption spectroscopy and x-ray magnetic circular dichroism have been applied to study the oxidation reactions at the buried interface resulting from NiO deposition on Fe(001). The NiO layer is obtained by reactive deposition; i.e., by evaporating Ni in an O2 atmosphere. We find that NiO reactive deposition on Fe(001) promotes Fe oxidation, leading to the formation of a thick, oxygen-rich oxide, identified as Fe3O4. This ferrimagnetic interface oxide shows a net magnetization that couples ferromagnetically to the iron substrate. This behavior is different from the case of the Fe/NiO(001) interface, where formation of (antiferromagnetic) FeO occurs. A sample annealing following the growth of the NiO/Fe interface is found to reduce the iron and to induce Ni diffusion in the Fe substrate.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
