Synthesis of Monodisperse Iron Nanoparticles with a High Saturation Magnetization Using an Fe(CO)_x−Oleylamine Reacted Precursor

Abstract

Monodisperse Fe nanoparticles with a high saturation magnetization were synthesized by thermal decomposition of a newly developed Fe(CO) x -oleylamine reacted precursor. The coordinate bond of the Fe(CO) x -oleylamine reacted precursor is different from conventional Fe(CO) 5 , and the CO ligands are partially replaced by oleylamine. The coordinate bond of the Fe(CO) x -oleylamine reacted precursor had a large influence on the size of the Fe nanoparticles, and as a result, the nanoparticle diameter could be controlled in the range from 2.3 to 10 nm by changing the reaction temperature and time for the precursor. The saturation magnetizations for 10 and 2.3 nm diameter NPs were 192 and 160 emu/g Fe at 5 K. The high M S of the Fe NPs was attributed to lesser amounts of impurities, such as C and O.

Improvement of saturation magnetization of Fe nanoparticles by post-annealing in a hydrogen gas atmosphere

“…Fe NPs with a narrow diameter distribution in the range from 3 nm to 10 nm have been realized using the thermal decomposition of an Fe(CO) 5 -oleylamine reacted precursor. 4 However, the maximum M s of the resultant Fe NPs was 163 emu/g Fe , observed for a particle diameter of 10 nm, which is no more than 75% of the M s for bulk Fe. Fe NPs synthesized by the thermal decomposition of an Fe(CO) 5 -oleylamine reacted precursor have an amorphous-like structure.…”

Planar Hall ring sensor for ultra-low magnetic moment sensing

“…A magnetic biosensor detects biomarkers through the local stray field of their magnetic labels that are biologically bound to the sensor surface, under an external magnetic field. 1 Because the sensor resolution is proportional to the detection capability of the magnetic moment, both the development of high magnetic moment labels such as Fe, CoFe, Fe@Fe 3 O 4 nanoparticles, or nanoparticles of antiferromagnetic materials, [2][3][4][5][6] and high field sensitive magnetoresistive sensors 7 are highly desirable.…”

Effect of Nucleation and Growth Dynamics on Saturation Magnetization of Chemically Synthesized Fe Nanoparticles

“…In order to synthesize Fe NPs with much higher M s , decrease in size of the initial nucleus should be needed by higher stabilization of small initial nucleus and/or seeding with sub-nano scaled cluster. In our recent study [10], by applying newly developed a Fe(CO) x -Oleylamine reacted precursor, higher M s values of 192 emu/g Fe could be obtained for 10.0 nm in diameter and 160 emu/g Fe even for 2.3 nm due to lesser amounts of impurities. In this synthesis, highly stabilized small initial nucleus may also be possibly achieved because 2.3 nm of the particle size is much smaller than the present smallest size (4.2 nm-6.2 nm) of the Fe NPs synthesized using Fe(CO) 5 even after 1 min.…”