Nanostructure and magnetic properties of highly (001) oriented L1_0 (Fe_(49)Pt_(51))_(1-x)Cu_x films

摘要

We report on nonepitaxially grown L1_0 Cu-alloyed FePt thin films with strong (001) texture. The FePt films with different Cu contents were deposited directly on Si wafers with a Fe_(49)Pt_(51)/Cu multilayer structure. The Cu content was varied from 0 to 13 at. %. All films were annealed at 600 ℃ for 5 min. X-ray-diffraction characterization showed that only one set of L1_0 diffraction peaks appeared and no elemental Cu diffraction peaks were visible. This result, along with a varying c/a lattice-parameter ratio, suggests that Cu substitutes Fe or Pt in the L1_0 lattice and ternary FePtCu alloy films are formed. (001) texture was enhanced with the increase of Cu content. Transmission electron microscope images showed that the grain size of FePtCu was about 10 nm. For FePt film with 11 at. % Cu substitution, coercivity was about 5 kOe, which is suitable for writing in a practical perpendicular-recording film.