Exchange coupled composite media for perpendicular magnetic recording

A novel exchange coupled composite (ECC) media was demonstrated and investigated systematically in this work. The writing capability and thermal stability were proved to be engineered separately based on this new media. Proper exchange coupling between [Co-PdSiO]_n hard layer and FeSiO soft layer was implemented through a PdSi interlayer. Transmission electron microscope plan-view and cross section view observations, macromagnetic, and micromagnetic testing proved vertically grown magnetic grains with soft and hard regions for ECC media. The switching of the soft region of magnetic grains with the external field rotated the magnetization of the hard region of magnetic grains to about 45° with perpendicular direction, which resulted in a similar behavior as a dynamic tilted media. A much lower angle dispersion of the remanent coercivity for the ECC media was found, which is another advantage for such media. ECC media showed better recording performance compared to perpendicular media. Strong exchange coupling between the hard and soft regions of magnetic grains (exchange spring media) was discussed based on the above proposed layer structure too.