FePt fct-[001] texture prepared at lower temperature for high areal density perpendicular recording

FePt thin films with face-centered-tetragonal (fct)-(001) texture have been prepared by magnetron sputtering at elevated temperatures from 350°C to 450°C. A Cr_100-xRu_x underlayer was used to induce the FePt fct-(001) texture. The dependence of the texture on Ru content and substrate temperature is investigated. The Cr lattice constant was expanded by addition of Ru, resulting in a bigger lattice mismatch between the Cr(200)-FePt(001) planes. Greater fct phase with c axis oriented perpendicular to the film plane has been achieved in films with a Cr₉₁Ru₉ underlayer. This result may arise from the strain-enhanced preferred orientation. The increase of substrate temperature favors the formation of fct-(001) texture. However, higher substrate temperature results in less fct phase formation. This may be caused by the diffusion of Cr from the underlayer into the magnetic layer.