Film Composition and Perpendicular Magnetic Anisotropy of Electroless-Plated CoNiReP Films

The magnetic properties and microstructure of electroless-plated CoNiReP films, which varied primarily in their cobalt content, were investigated in order to clarify the origin of their magnetic anisotropy. The films which showed perpendicular magnetic anisotropy contained approx. 25 to 40% cobalt. They also had a higher crystallinity and better c-axis orientation than does hep cobalt. It is thought that the anisotropy of these films is mainly due to the crystalline anisotropy deriving from the micro structure, and that the smaller M
S
values, which act to decrease the demagnetizing field, enhance the anisotropy. The shape anisotropy caused by segregation in films is also thought to affect the overall anisotropy.