Columnar structural FePt films with good perpendicular anisotropy induced by tuning the crystal structure of doping materials

Abstract

Crystalline ZrO2 doping would degrade the perpendicular texture of FePt films due to the epitaxial growth of FePt (200) textured phase on the tetragonal (002) textured ZrO2. In the present paper, crystalline HfO2 was used to replace crystalline ZrO2 as the crystalline doping material and FePt media with columnar structure and good perpendicular anisotropy were achieved. It is found that HfO2 crystallized on TiON intermediate layer presented the coexistence of both monoclinic and tetragonal phase. The extremely large lattice mismatch strain (around 25–28%) between FePt and HfO2 would prohibit the (200) or (001) epitaxial growth of FePt phase on HfO2. This would cause FePt-HfO2 film to have better (001) texture and perpendicular anisotropy compared to FePt-ZrO2 films. By tuning the crystal structure of doping crystalline phase material, columnar structural FePt films with better perpendicular anisotropy could be obtained, which may offer a method for the application of FePt media in heat assisted magnetic recording.