Facile Nanotube-Assisted Synthesis of Ternary Intermetallic Nanocrystals of the Ferromagnetic Heusler Phase Co₂FeGa

Abstract

A facile synthesis approach for the synthesis of ternary intermetallic nanocrystals was demonstrated exemplarily with the Heusler compound Co2FeGa. The method, involving prefabricated multiwalled carbon nanotubes which act as a template and protective shell, results in the formation of mainly spherical, chemically stable, and crystalline nanoparticles with a well-defined diameter distribution. As an example, for novel functionalities arising from downscaling a bulk material, we observe an enhancement of the coercive field of the Co2FeGa nanocrystals by a factor of ≈30. Our work can facilitate the exploration and eventually the tuning of physical properties of ternary and other intermetallic compounds at the nanoscale.

Single-crystalline FeCo nanoparticle-filled carbon nanotubes: synthesis, structural characterization and magnetic properties

“…TGA is mainly used as a measure of the sample purity (i.e., the absence of outside particles which exhibit an increase in mass prior to the combustion of the CNTs), and for the determination of the filling material inside CNTs by performing back calculations based on the mass of the TGA residue [48–49]. This measurement confirms the observations found by SEM that the main difference between the two filling approaches is the filling yield, i.e., samples prepared by the second filling approach are found to have a higher filling yield in comparison with those prepared by the first (solution) filling approach.…”

The emergence of Heusler alloy catalysts

“…L2 1 -Co 2 FeGa nanoparticles with an average particle size of around 20 nm were successfully synthesized on fumed silica supports by impregnation, although a relatively small amount of extra phases existed in addition to the L2 1 phase [32][33][34][35]. The synthesis was also achieved by impregnation into facile carbon nanotubes [36]. The synthesis of L2 1 -Co 2 FeAl nanoparticles was also reported [37,38].…”

Magnetic properties of individual Co2FeGa Heusler nanoparticles studied at room temperature by a highly sensitive co-resonant cantilever sensor

“…Magnetic nanoparticles are of high interest in many fields of research, reaching from magnetic storage techniques and spintronics 1 , 2 to biomedical applications which include drug delivery and hyperthermia treatment 3 – 5 . Recently, nanoparticles and -wires made of Heusler compounds have come into focus of research, due to their many potential applications in the aforementioned fields 6 – 8 . They can be grown with different aspect ratios, ranging from almost spherical nanoparicles to nanowires 1 , and might as well be encapsulated in carbon nanotubes to control size and shape of the particles 8 .…”

“…Recently, nanoparticles and -wires made of Heusler compounds have come into focus of research, due to their many potential applications in the aforementioned fields 6 – 8 . They can be grown with different aspect ratios, ranging from almost spherical nanoparicles to nanowires 1 , and might as well be encapsulated in carbon nanotubes to control size and shape of the particles 8 . First investigations have been carried out to analyze and understand the magnetic behavior of these Heusler nanomaterials 2 , 6 , 8 – 10 .…”