Improved magnetic properties and texture of FePt-C thin films doped with Ti or Zr

L1₀-ordered FePt thin films with large magnetocrystalline anisotropy, widely known to be the next candidate for ultra-high density heat assisted magnetic recording, media, has garnered significant attention. Much of the work done on FePt primarily focused on grain size reduction and improvements in magnetic properties. Obtaining small FePt grains typically involved the doping of secondary materials such as various oxides, nitrides, or single elements into FePt. Of these dopants, C is the most widely used dopant as when added to FePt, had shown large coercivities as well as small grain sizes. However, one problem faced by the usage of C is its high mobility resulting in carbon diffusing upwards covering FePt surfaces during the deposition process. This results in the formation of dual layer structures consisting of soft FCC FePt particles on L1₀-ordered FePt grains[i]. Thus in our work, either Ti or Zr was added to FePt-C in order to control the diffusion of C through the formation of carbides, improving the texture, and magnetic properties of FePt.