Direct Synthesis and Size Selection of Ferromagnetic FePt Nanoparticles

Abstract

A one-step synthesis of L10 FePt nanoparticles ca. 17.0 nm in diameter by reductive decomposition of the single-source precursor, FePt(CO)4dppmBr2, on a water-soluble support (Na2CO3) is demonstrated. Direct conversion of a FePt(CO)4dppmBr2/Na2CO3 composite to a L10 FePt/Na2CO3 nanocomposite occurs at 600 °C under getter gas with metal-ion reduction and minimal nanoparticle coalescence. Triturating the resulting nanocomposite with water simultaneously dissolves the sodium carbonate solid support and precipitates the formed fct FePt nanoparticles. As-prepared FePt nanoparticles are ferromagnetic and exhibit coercivities of 14.5 kOe at 300 K and 21.8 kOe at 5 K. When capped by functionalized methoxypoly(ethylene glycol) surfactant molecules, as-prepared, polydisperse ferromagnetic FePt nanoparticles can be dispersed and size-selected by fractional precipitation.

Synthesis of magnetic rhenium sulfide composite nanoparticles

“…Moreover, it is interesting to note that the magnetic nanoparticles exhibit a superparamagnetic behavior with zero coercivity after they are modified by MPEG-COOH, which benefit their applications in medicine. Similar behavior was reported by Wellons et al [43] that magnetic particles would have a degressive trend of coercivity when they were modified with MPEG.…”

A Polyferroplatinyne Precursor for the Rapid Fabrication of L10‐FePt‐type Bit Patterned Media by Nanoimprint Lithography

“…Hence, some organometallic complexes containing both Fe and Pt atoms for use as a single source precursor were synthesized and applied to generate the L1 0 phase FePt NPs by the one-step decomposition. [8,9] However, direct and rapid patterning of the target FePt NPs is also a substantial challenge for many practical applications, which demand precise reading out and direct-writing onto the NPs. In particular, bit patterned media (BPM) made with FePt NPs are promising candidates for the next generation of magnetic recording systems.…”

Patterning of L10FePt nanoparticles with ultra-high coercivity for bit-patterned media

“…Besides, although this method demonstrates the feasibility to produce nanocrystals with smooth morphologies, the dual-source precursors involved such as Fe(CO)5 or Fe(acac)2 and Pt(acac)2, also bring about the difficulty for stoichiometric control. [30][31][32] Recently, single-source organometallic precursors such as (CO)3Fe(μ-dppm)(μ-CO)PtCl2 and FePt(CO)4dppmBr2 were reported, [33][34][35][36][37] in which the atomic ratio of Fe and Pt could be easily controlled. In such case, the precursors would decompose at the same decomposition temperature and the two types of metal atoms are homogeneously distributed in the organic framework at the molecular scale, which would be beneficial to prevent the agglomeration of FePt NPs.…”