We have synthesized hcp-Co fine particles with the average diameter of less than 50 nm by sputtering Co in a somewhat high inert gas pressure. A nearly perfect hcp phase can be stabilized by increasing sputtering gas pressure and decreasing sputtering power in contrast to conventional preparation conditions. Magnetic measurements have revealed the clear relation of coercivity with the volume ratio of hcp phase. That is, the increase in the hcp phase considerably enhances the coercivity. Appearance of the hcp phase seems to be related to the promotion of allotropic phase transformation in Co initiated by lattice defects within each particle.
ASJC Scopus subject areas
- Physics and Astronomy(all)