Epitaxial Growth of L1 $_{0}$–FePt Granular Thin Films on TiC/RuAl Underlayers

Highly ordered L1
$_{0}$
FePt-oxide thin films with perpendicular texture and small grains were fabricated on a TiC underlayer along with a RuAl small grain size layer and a MgO seedlayer. The epitaxial growth from the MgO seedlayer to the TiC
$\backslash$
RuAl grain size defining underlayer to FePt magnetic layer was studied. Perpendicular texture can be further improved by adjusting the thickness of each layer to optimize the in-plane stain. From our microstructure study, TiC/RuAl grain size defining layer was found effective in reducing the volume fraction of oxide in the film and the center-to-center grain size of FePt grains. With a thin Ag sacrificial layer inserted between TiC and FePt magnetic layer, a smaller grain size can be achieved, the ordering temperature was lowered, and the (001) texture of FePt was enhanced.