Microstructure of coevaporated CoCr films with perpendicular anisotropy

Coevaporation of Co and Cr is applied to achieve good magnetic characteristics of media deposited at low temperature. The opposed oblique incidence vapor flux induces a columnar alignment parallel to the evaporation plane. Further, a process-induced segregation is present which introduces separated Co-rich and Cr-rich regions. A selective etching process is carried out to find proof of this. With increasing process temperature, nonelongated columns develop. The columnar axes are inclined towards the Co source at a smaller angle than the angle of incidence. The texture axes are also inclined, as are the anisotropy axes. The process-induced segregation results in an enhanced coercivity and saturation magnetization. A small in-plane anisotropy coincides with the direction of columnar alignment. At a higher process temperature, the column, texture, and anisotropy axis tilting decreases.<
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