Magnetoresistance Effect of a Co/γ-Fe/Co Trilayer

Surfactant Effect of Oxygen Atoms on Epitaxial Growth of fcc Ultra Thin Films on Cu(001)

“…Then, the buffer surface was exposed to the oxygen gas until 1800 L as mentioned above. In our previ- ous investigation on the Co/γ -Fe/Co trilayer 7) deposited on a clean Cu(001) surface, it was reported that the γ -Fe in the Co/γ -Fe/Co trilayer was so unstable that it could not be grown over 7 ML (= 1.26 nm) in the case of using Cu buffer layer (100 nm) deposited on MgO(001). We prepared a Co(1 nm)/γ -Fe(1.8 nm)/Co(1 nm) trilayer on the Cu(100 nm) buffer deposited on MgO(001) substrate, utilizing the surfactant effect of oxygen atoms for stabilize of Co/γ -Fe/Co trilayer.…”

“…We already reported the preparation and magnetic properties of Co/γ -Fe/Co trilayer film. 7) The small MR ratio was, however, reported due to the difficulty of the preparation of high quality Co/γ -Fe/Co trilayer, where it was a problem that the γ -Fe is an unstable phase at room temperature, and it grows up to only 11 ML (1 ML = 0.180 nm) on the clean Co(001) 8) or on the clean Cu(001) [9][10][11] single crystal substrate. However, the critical thickness of γ -Fe depends on the surface roughness of the substrate.…”

“…However, the critical thickness of γ -Fe depends on the surface roughness of the substrate. In our previous study, 7) in the case of growth on the Cu buffer (100 nm) layer deposited on MgO(001), the critical thickness was 7 ML, which was insufficient for studying the large MR ratio. Now, it is well known that the surfactant effect in the growth of ultra thin film could improve the interface flatness of the multilayer 12) and make the growth mode layerby-layer.…”