Fabrication of oriented L1₀-FeCuPd and composite bcc-FeL1₀-FeCuPd nanoparticles: Alloy composition dependence of magnetic properties

Oriented and well-isolated L 10 -FeCuPd ternary alloy nanoparticles have been fabricated by electron-beam evaporation followed by postdeposition annealing. A single L 10 phase was formed in the FeCuPd nanoparticles with (Fe+Cu) content lower than 48 at. %. A strong preferential c -axis orientation along the film normal direction was achieved by Cu addition, which leads to a strong perpendicular magnetic anisotropy. Also, a lowering of the ordering temperature by 50 K compared to the binary L 10 -FePd nanoparticles was achieved by Cu addition. By contrast, composite particles composed of the bcc Fe and the L 10 -FeCuPd were formed when the (Fe+Cu) content was higher than 52 at. %. Coexistence of the bcc Fe and the L 10 -FeCuPd was confirmed by high-resolution transmission electron microscopy and nanobeam electron diffraction. It was found that perpendicular magnetic anisotropy of the L 10 -FeCuPd nanoparticles on the NaCl substrate is sensitive to the alloy composition. © 2006 American Institute of Physics.Hiroshi Naganuma, Kazuhisa Sato, and Yoshihiko Hirotsu, "Fabrication of oriented L1₀-FeCuPd and composite bcc-Fe/L1₀-FeCuPd nanoparticles: Alloy composition dependence of magnetic properties", Journal of Applied Physics 99, 08N706 (2006) https://doi.org/10.1063/1.2165604

Perpendicular magnetic anisotropy of epitaxially grown L1₀-FePdCu nanoparticles with preferential c -axis orientation

Oriented and well-isolated 14-nm -sized Fe₄₁ Pd₅₂ Cu₇ ternary alloy nanoparticles with the L 1₀ -type ordered structure have been fabricated by the sequential deposition of Pd, Cu, and Fe on NaCl (001) substrate followed by postdeposition annealing. The annealing temperature required to obtain a high coercivity decreased by at least 50 K upon the addition of a small amount of Cu. Furthermore, it was revealed that a strong preferential c -axis orientation along the film normal direction was achieved by the addition of Cu, which resulted in a strong perpendicular magnetic anisotropy. The population of the nanoparticles with their c -axis oriented normal to the film plane was 74%. The alloy composition was independent of the particle size, as determined by energy dispersive x-ray spectroscopy using nanoprobe electrons. Nanobeam electron diffraction revealed that the axial ratio is constant for FePdCu nanoparticles with sizes between 10 and 25 nm. Interparticle magnetostatic and exchange interactions played an insignificant role in the isolated FePdCu nanoparticles. The correlation between their preferential c -axis orientation and magnetic properties is discussed based on the rotation magnetization of single magnetic domain particles. © 2006 American Institute of Physics.Hiroshi Naganuma, Kazuhisa Sato, and Yoshihiko Hirotsu, "Perpendicular magnetic anisotropy of epitaxially grown L1₀-FePdCu nanoparticles with preferential c-axis orientation", Journal of Applied Physics 100, 074914 (2006) https://doi.org/10.1063/1.2357420