FeCuPt nanodot arrays were fabricated by electrodeposition onto a nano-pore patterned substrate fabricated by electron beam lithography (EBL), for the purpose to manufacture and characterize model bit-patterned media (BPM). Addition of Cu to FePt was carried out to accelerate the phase transformation of FePt into the L10-ordered phase in order to fabricate nanodot arrays with hard and uniform magnetic properties. Composition of the FeCuPt ternary alloy films was optimized by varying applied potential and CuSO4 concentration to form single L10 phase (40~50 at% Pt and ~25 at% Cu). Annealing at 450 °C resulted in the phase transformation from fcc to L10 in FeCuPt ternary alloy films, whereas FePt binary alloy films did not show a phase transformation. Perpendicular coercivities of FeCuPt and FePt were 6.0 and 1.0 kOe, respectively, annealing at 450 °C, indicating the formation of the L10 phase with lower annealing temperature by Cu incorporation. FeCuPt nanodot arrays with 20 nm in diameter and 35 nm in pitch were successfully fabricated with the nano-pore patterned substrate fabricated by EBL. In addition, cross-sectional transmission electron microscope (TEM) analysis of FeCuPt nanodot arrays showed clear stacking of the L10 (111) lattice in a perpendicular direction through the growth direction having a single crystal nature, whereas phase transformation was insufficient with FePt nanodot arrays. The collective results have successfully demonstrated the electrochemical fabrication of ultra-fine FePt nanodot arrays with L10 structure by promoting L10 ordering with Cu additions.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering