Direct chemical synthesis of L1₀-FePtAu nanoparticles with high coercivity

Abstract

We report a facile synthesis of hard magnetic L10-FePtAu nanoparticles by coreduction of Fe(acac)3, Pt(acac)2 (acac = acetylacetonate), and gold acetate in oleylamine. In the current reaction condition, NP sizes are controlled to be 5.5 to 11.0 nm by changing the amount of Au doping. When the Au composition in the NPs is higher than 14%, the hard magnetic NPs are directly obtained without any annealing. The highest coercivity of 12.15 kOe at room temperature could be achieved for the NPs with 32% Au doping, which is much higher than the coercivities reported by the previous studies on solution-synthesized FePt nanoparticles. The reported one-pot synthesis of L10-FePtAu NPs may help to build superstrong magnets for magnetic or data-storage applications.

Synthesis of a High-Coercivity FePt–Ag Nanocomposite Magnet via Block Copolymer-Templated Self-Assembly

“…The coercivity of the sample synthesized with Ag was much higher than the reported values for chemically synthesized FePt nanocomposites [19][20][21][22]. This suggests that the increase in the coercivity was caused by the addition of Ag to the FePt nanocrystals and that the grain boundaries of the nonmagnetic Ag metal acted as pinning sites, disrupting magnetic coupling between individual FePt nanocrystallites and hindering domain wall motion at an external magnetic field.…”

“…Fabrication of FePt nanostructures by chemical synthesis is a promising alternative, but achieving high coercivity with chemical synthesis methods has been difficult [19][20][21][22]. The problem has been attributed to the difficulty of controlling nanocomposite structures.…”

Face Centered Cubic Co81.8Si9.1B9.1 With High Magnetocrystalline Anisotropy

“…The small M s is not likely due to the dilution effect of the substituted elements. Such reduced M s was also observed in many CoPt and FePt nanoparticles . It is also reported the M s could be increased significantly in FePt by tuning the 3 d ‐5 d interaction via the minor addition of Au .…”

“…Such reduced M s was also observed in many CoPt and FePt nanoparticles. [18][19][20] It is also reported the M s could be increased significantly in FePt by tuning the 3d-5d interaction via the minor addition of Au. [20] Thus the reduced M s should result from the partial delocalization of Co 3d electrons likely induced the strong interaction with B or Si.…”

Chemical synthesis of L1 Fe-Pt-Ni alloy nanoparticles

“…Most reports focus on the addition of a third element dopant keeping the stoichiometry between Fe and Pt fixed with the purpose of reducing ordering temperature. [17][18][19][20][21][22][23] To our knowledge only one other study considered the chemical synthesis of an Fe-Pt-Ni alloy, in which (FePt) 1-x Ni x nanoparticles were obtained. It was shown that the addition of Ni in an FePt phase suppresses the transformation from the disordered fcc to the ordered fct L1 0 phase, up to a certain Ni content, beyond which nanoparticles in the L1 2 phase are obtained.…”