Magnetic‐Field‐Induced Phase‐Selective Synthesis of Ferrosulfide Microrods by a Hydrothermal Process: Microstructure Control and Magnetic Properties

Abstract

Microrods of the ferrosulfide minerals greigite (Fe3S4) and marcasite (FeS2) are selectively synthesized by an in situ magnetic‐field‐assisted hydrothermal route. Each complex microrod is composed of fine building blocks with different shapes. The unique magnetic properties of the microrods and electrical performance of a single microrod are studied. The results demonstrate that the magnetic properties of the ferrosulfide minerals are strongly related to their corresponding microstructures. The value of the low‐temperature transition increases as the greigite component in the product decreases. The combination of small‐molecule sulfur precursors and an applied magnetic field makes possible the selective synthesis of ferrosulfide minerals with different phases and distinct microstructures, underlining the fact that the magnetic field can be a useful tool as well as an independent parameter for the phase‐selective synthesis and self‐assembly of inorganic building blocks in solution chemistry.

Fabrication and characterization of nanostructured Fe3S4, an isostructural compound of half-metallic Fe3O4

“…Figures 1(c) and 1(d) illustrate the formation of Fe 3 S 4 microflowers, each consisting of a number of nanoplatelets 5-8 lm in width and length and 0.5 lm in thickness. The gaps between these larger micron-sized platelets are filled with much smaller platelets, consistent with observations by Cao et al 20,21 We performed energy-dispersive X-ray spectroscopy (EDX) and element mapping to learn more about the elemental composition and distribution in these microflowers ( Figure 1(d)). The signal of aluminum is from the sample holder.…”

Physical Properties of Elongated Magnetic Particles: Magnetization and Friction Coefficient Anisotropies

“…This method was further improved in 2007 by Vereda et al (see Figure 9), who produced micron-sized rodlike magnetite [68] and non-stoichiometric Ni and Co ferrite [104] particles by magnetic-field-induced self-assembly for magnetorheological applications. Finally, He and co-workers [105] employed a magnetic field to induce the formation of ferrosulfide micro-rods as well as to control the crystalline phase of the resulting material.…”

Magnetic field-induced solvothermal synthesis of one-dimensional assemblies of Ni-Co alloy microstructures

“…In recent years, a few groups have employed magnetic fields to assemble magnetic materials in order to obtain onedimensional nanostructures. For example, nickel wires and Fe 3 O 4 nanowires have been synthesized under the influence of magnetic fields [31 33], phase-selective synthesis of ferrosulfide microrods has been realized by a hydrothermal process using an amino acid additive under the influence of an external magnetic fi eld [34], Wang et al synthesized necklace-like noble metal hollow nanoparticle chains by using necklace-like Co nanoparticle chains, previously synthesized in a magnetic field-induced process, as a sacrificial template [35], and Gu et al demonstrated the alternating current magnetic fi eldinduced assembly of magnetite nanoparticles and its close relationship with the surface charge [36]. In addition, magnetic fields have also been used to direct the alignment of vanadium pentoxide ribbons [37], mouse osteoblast cells [38], carbon nanotubes [39], and polystyrene nanoparticles in an aluminum ferrite layered block [40].…”