Microstructural study of electroless-plated CoNiP ternary alloy films for perpendicular magnetic recording media

The microstructure of electroless CoNiP films with various H _c(⊥) values for use as perpendicular magnetic recording media was investigated. It was observed that the H _c(⊥) values of the films varied according to their microstructure. The film which showed the highest H_c(⊥) value contained large columnar grains with high crystallinity, whereas such a clear columnar structure was not observed in the films with lower H_c(⊥) values. The shape anisotropy due to the columnar structure effectively contributes to the magnetic properties of the films as well as magnetocrystalline anisotropy associated with preferred crystallographic orientation. The results of compositional analysis of ultra-small regions suggested that the formation of low M_s and low H_c regions at the initial deposition stage was due to a preferential deposition of Ni