Domain structure and microstructure of CoNi oblique incidence thin films

Abstract

The magnetic properties of thin films produced by vacuum evaporation depend on the deposition conditions, such as incident angle(α) and substrate temperature. These effects have been investigated in CoNi oblique incidence thin films by transmission electron microscopy. Both incident angle and substrate temperature are observed to have significant effects on the magnetization easy direction in the films. Low‐angle films (α≤60°) are magnetically continuous with in‐plane easy axes and reverse their magnetization by domain wall motion. On the contrary, high‐angle films are magnetically isolated with an out‐of‐plane easy axis and reverse their magnetization by an incoherent rotation process. Microstructural results show that a c‐axis texture increases with increasing incident angle. In high‐angle films, the columns are single crystals and have a high defect density. The c axis of the columns does not coincide with the column axis. Thus, it is concluded that the origin of the magnetic anisotropy in low‐angle films is mainly due to shape anisotropy. On the other hand, in high‐angle films, crystalline anisotropy and stress anisotropy should be taken into account in addition to the shape anisotropy.