Reduced graphene oxide-magnetite hybrid aerogels attract great interest thanks to their potential applications, e.g., as magnetic actuators. However, the tendency of magnetite particles to migrate within the matrix and, ultimately, escape from the aerogel structure, remains a technological challenge. In this article we show that coating magnetite particles with polydopamine anchors them on grap...

The Stober process is frequently used to prepare silica-coated iron oxide nanoparticles. This is usually achieved by seeding a reaction mixture consisting of water, ethanol and a catalyst with iron oxide particles and adding a silica precursor. The hydrolysis and condensation of precursor monomers results in the deposition of a silica layer on iron oxide particles. However, this process is acco...

I-Xe ages of Murchison and Orgueil magnetites were reported to be the oldest [1] and interpreted as the condensation time of the solar nebula. More recent measurements, conducted on a highly magnetic separate from Orgueil (but not pure magnetite), gave much younger I-Xe ages [2]. We have since performed new studies on two pure separates of Orgueil magnetite, confirming the later closing time of...

We evaluate the application of 57Fe Mössbauer spectroscopy to the determination of the composition of magnetite (Fe3O4)/maghemite (γ-Fe2O3) mixtures and the stoichiometry of magnetite-maghemite solid solutions. In particular, we consider a recently proposed model-independent method which does not rely on a priori assumptions regarding the nature of the sample, other than that it is free of othe...

The understanding of the key mechanisms behind human brain deterioration in Alzheimer' disease (AD) is a highly active field of research. The most widespread hypothesis considers a cascade of events initiated by amyloid-β peptide fibrils that ultimately lead to the formation of the lethal amyloid plaques. Recent studies have shown that other agents, in particular magnetite, can also play a pivo...

We compare the magnetic properties of fine‐grained magnetite produced by two newly isolated anaerobic bacteria, a magnetotactic bacterium (MV‐1) and a dissimilatory iron‐reducing bacteriu m (GS‐ 15). Although room‐temperature magnetic properties are generally different between the two microorganisms, MV‐1 and GS‐15 magnetites can be most easily distinguished by the temperature variation of satu...

In situ synthesis of magnetite particles has been carried out in a preorganized polyvinyl alcohol (PVA) gel by varying the total number of iron ions in an environment of a fixed number of hydroxyl functional groups of PVA. A systematic change in the morphology and patterning of the magnetite particles on the polymer surface revealed the effect of the total number of cations on the conformation ...

In a hydrothermal preparation of crystalline magnetite (Fe3O4) nanoparticles, the influence of the experimental parameters (initial molar ratio of ferrous/ferric ions, initial concentration of ferrous ions, and heating time), and their interactions, on the particle formation was studied using response surface methodology (RSM), based on a statistical design of experiments (DOE). As indices indi...

Monoclinic pyrrhotite from Norseman, Western Austra"lia, has lamellae of submicrometer thickness, identified by microprobe and electron diffraction as magnetite. The lamella zurface is (111) of magnetite parallel to (001) of pyrrhotite, corresponding to a close fit of close-packed planes of the two structures' The perfect lamellar nature of the magnetite in unaltered pyrrhotite indicates origin...