Fabrication and properties of Fe/Fe oxide and Co/Co oxide films

Evaporation of Fe and Co at a residual O
2
pressure of 10
^-5
to 10
^-4
Torr yielded magnetic films of high coercivities up to 500 Oe and magnetizations of about 1000 EMU/cm
³
. While the Co films were continuously deposited in the O
2
atmosphere, a sandwich structure of Fe and Fe
2
O
3
was formed by intermittently altering the evaporation conditions. Both kinds of films were produced in the same geometrical arrangement. The Fe/Fe
2
O
3
films showed shape anisotropy caused by the oblique incidence deposition, while no uniaxial anisotropy was observed on the Co films. For both, Co films and Fe/Fe
2
O
3
sandwich films, it was possible to adjust the magnetic properties within a certain range. In both cases the coercivity increased considerably by annealing at 200°C.