The Network-Shaped Upheaval Structure in (002) Textured MgO Layer for L10 FePt-Based Granular Media With Columnar Nanostructure

Search for amorphous materials with high crystallization temperature and investigation of crystal orientation, surface morphology, and composition distribution of MgO/bcc-Cr80Mn20/amorphous-Co60W40 underlayer were conducted. As a result, the crystallization temperature of amorphous-Co60W40 is higher than 620 degrees C and it proved to be suitable as texture inducing layer material. Also, it was found that a network-shaped upheaval structure corresponding to the grain size of the (002) plane oriented CrMn grains was formed on the surface of the (002) plane oriented MgO layer. By utilizing the surface roughness of the underlayer, we proposed a columnar isolated granular medium for heat-assisted magnetic recording (HAMR) by using the FePt-oxide granular layer/pure FePt islandlike initial nucleus layer/networklike upheaval underlayer.