Evaporated amorphous GdCo-films with perpendicular anisotrophy by controlled oxygen contamination

Vacuum deposited amorphous GdCo-films with strong perpendicular magnetic anisotropy were prepared by thermal evaporation of the constituents at an oxygen pressure during film fabrication between 2.5 × 10
^-8
Torr and 2 × 10
^-7
Torr. K
u
-values above +2.3×10
⁵
erg/cm
³
at 4 ±M
s
= 1000 Gauss were obtained in this pressure range. The coercivity of films with 4 ±M
s
= 1000 Gauss increases from 15 Oe at 2.5 × 10
^-8
Torr to 150 Oe at 1.5 × 10
^-7
Torr O
2
. In this paper the fabrication technique of these films is described and the measured magnetic and physical properties are reported and discussed. A model to explain the origin of the perpendicular anisotropy is proposed.