@article{Miot2014FormationOS, title={Formation of single domain magnetite by green rust oxidation promoted by microbial anaerobic nitrate-dependent iron oxidation}, author={Jennyfer Miot and Jinhua Li and Karim Benzerara and Moulay Tahar Sougrati and Georges Ona-Nguema and Sylvain Bernard and J. -C. Jumas and François Guyot}, journal ...
The pressure dependence of electrical resistance of single-crystal magnetite (Fe3O4) was measured under quasi-hydrostatic conditions to 100 GPa using low-temperature, megabar diamond-anvil cell techniques in order to gain insight into the anomalous behavior of this material that has been reported over the years in different high-pressure experiments. The …
pseudo-single-domain magnetite over billion-year timescales. Pr oceedings of the National Academy of Sciences of the United States of Amer - ica, 114 (39), 10356–10360.
Request PDF | Single crystalline magnetite, maghemite, and hematite nanoparticles with rich coercivity | One-pot synthesis of amorphous iron oxide nanoparticles with two different dimensions ...
In this paper, single-crystal magnetite hollow sub-microspheres with a narrow diameter distribution are synthesized through a simple solvothermal process in ethylene glycol in the presence of urea and a small amount of water. The determining role of water in the solvothermal synthesis is studied. It is found that a small amount of water is crucial for the …
Single-phase magnetite was only achieved at φ = 0.95. Conducting the reaction at φ = 1 raised the ability of provided reducing atmosphere by H 2 and CO, and led to the formation of wustite phase. Modified method resulted in porous nano-particles with a particle size in the range of 20–70 nm. The ...
A unique form of tabular, single-domain magnetite is produced under nontraditional (low-CO(2)) culture conditions and has a distinct crystal habit and magnetic properties that could be used as a biosignature to recognize ancient biological activities in terrestrial and extraterrestrial environments. Distinct morphological characteristics of …
orientation of each single nanoparticle according to the Stoner-Wohlfarth model.. A recent article23 has applied the Stoner-Wohlfarth model in similar way to determine the magnetic anisotropy constant and the easy-axis orientation of 15 single magnetite nanoparticles in a bacterium using XMCD.
On the superparamagnetic—stable single domain transition for magnetite, and frequency dependence of susceptibility Abstract: Sediments and soils often contain superparamagnetic (SP) magnetite or maghemite grains that cause a frequency dependence of low-field susceptibility X fd which does not exceed 15 per cent/decade of frequency. Present ...
The methodology adopted for integration was reasonable in accordance with the sequence of phenomena which occurs during induration of magnetite pellet. Single Pellet Induration Model (SPIM) provides fruitful insights into the internal state or behaviour of magnetite pellet during induration reflecting upon the evolution of oxidation extent and ...
Furthermore, the grain size range for ideal single domain (SD) magnetic behavior in magnetite is narrow and fine-grained (i.e., ∼30 to ∼100 nm for equant grains [Dunlop and Özdemir, 1997; Muxworthy and Williams, 2009]) compared to the grain size distribution of most sediments. These observations mean that it should not be surprising that ...
The authors concluded that Mms6 controls magnetite size to obtain stable single domain particles both in vivo and in vitro. Mms6 C-terminus is hydrophilic and was postulated to accumulate iron ions, thereby triggering crystal nucleation and interacting with the magnetite nanoparticle surface, while the crystal is growing in vivo. ...
In this work, we have imaged and studied individual single-domain magnetite nanoparticles 20 nm in diameter by purely optical means. This is an improvement of about 4 orders of magnitude compared to our previous study of single multidomain magnetite nanoparticulate clusters of 400 nm in diameter. The detection sensitivity reaches about 4 × 10 ...
3 and from the side of the cubic unit cell of magnetite, 0.839 nm. With 32 Bohr magnetons per unit cell22, we expect a magnetic moment of 4.4×105 Bohr magnetons at saturation. Our MCD measurements enable us to record the full magnetization curves of single
Mimicking the bacteria's proteins using poly-l-arginine shows that by simply increasing the pH, the dimensions of magnetite increase and a single- to mesocrystal transformation is induced, and selectively produces superparamagnetic and stable single-domain particles merely by controlling the pH. Control over particle size, size distribution, and colloidal …
magnetization, M s) or are less sensitive (i.e., coercivity of remanence,B cr)tograinsizevariations.Plotsof variationsin hysteresis data, with M r/M s plotted versus B cr/B c [Day et al., 1977], have therefore become routine accompaniments to published papers in which magnetite grain size is important.
demonstrate magnetic CD imaging of superparamagnetic magnetite nanoparticulate clusters immersed in microscope immersion oil. The sensitivity of our method …
recorded from a ring of six magnetite particles demonstrates that each particle contains a single magnetic domain (Fig. 2a), while the ring configuration of the particles constrains the...
Using a novel extraction technique, transmission electron microscopy and SQUID magnetometry, it is shown that living magnetotactic bacteria and the magnetite they produce are the major source of stable remanent magnetism in these sediments. Remanent magnetism in marine sediments has been used extensively over the past twenty years to calibrate the geological …
Based on obtained results, it was shown that single-phase magnetite can be synthesized using glycine and citric acid only in an inert atmosphere. Deshpande suggested that interactions between ferric nitrate and fuel lead to the formation of magnetite which afterward reacts with atmospheric oxygen and converted to hematite. Ianoş et al. [5 ...
A new class of magnetite (Fe 3 O 4) particles, coined as "Single Crystalline Micrometric Iron Oxide Particles" (SCMIOPs), were obtained by hydrothermal synthesis.Both the single Fe 3 O 4 phase content and the particle sizes range, from 1 µm to 30 µm, can be controlled by synthesis. The notable finding states that these particles exhibit vanishing …
In this work, we present an in situ transmission electron microscopy (TEM) study of Fe thin films to Fe nanoparticle formation and their oxidation to single-crystal magnetite nanoparticles. Amorphous Fe thin films were prepared by sputtering on TEM carbon grids. The thin Fe films were continuously heated in situ from room temperature to 700 °C under vacuum …
Here, we report a label-free, machine learning-aided single-particle inductively coupled plasma mass spectrometry (spICP-MS) approach for tracing the exposure pathways of airborne magnetite nanoparticles (MNPs), including external emission sources, and distribution and translocation in vivo using a mouse model. Our results provide quantitative ...
This paper reports the first in situ magnetic hysteresis measurements of pseudo-single-domain (PSD) magnetite under high pressure up to 1 GPa. The magnetic hysteresis measurements of stoichiometric PSD magnetite samples under hydrostatic pressure were carried out using a piston-cylinder high-pressure cell, and the pressure dependence of the ...
Abstract. One-pot synthesis of amorphous iron oxide nanoparticles with two different dimensions (<5 nm and 60 nm) has been achieved using the reverse micelle method, with <5 nm …
In this study, the reduction characteristics of single magnetite particles with melting products at high temperature were investigated by using visualization and surface analytical techniques. The morphology evolution, product type, reduction degree, and reduction rate of single magnetite particles during the reduction process were analyzed and compared …
TEM micrographs of magnetite nanoparticles grown in the presence of different polycations for 24 h at pH 11. Corresponding selected area electron diffraction patterns, indexed according to the spinel crystal structure of magnetite are shown, indicating single-crystallinity for all nanoparticles.
Magnetite (Fe3O4) is an important magnetic mineral to Earth scientists, as it carries the dominant magnetic signature in rocks, and the understanding of its magnetic recording fidelity provides a ...
for single-domain magnetite 7 ; in fact, to date, all reported sizes of bacterial magnetites fall within this range 8-10• The irregular crystals may be produced by the dissolution of well-formed
Magnetite crystals formed by magnetotactic bacteria (magnetosomes) also have a variety of distinct morphologies. In particular, prismatic, elongated single-domain (SD) magnetite is produced intracellularly by a variety of magnetic bacteria in diverse environments (4-6). The formation of prismatic magnetite crystals has not been reported by any ...
Magnetofossils can be characterized quantitatively in bulk samples by magnetic methods. A single magnetofossil chain behaves similarly to a non-interacting stable single-domain (SSD) magnetic grain (e.g., Dunin-Borkowski …
To determine the optimum particle size, single-core magnetite nanoparticles with nominal average diameters 20, 25, 30 and 35 nm) were characterized by SQUID relaxometry, transmission electron microscopy, SQUID susceptometry, dynamic light scattering and zeta potential analysis. The SQUID relaxometry signal detected magnetic moment/kg) from both ...
Domain state in submicron-sized cubes of magnetite as defined by the magnetization structure: (a) single-domain (SD) state with nearly uniform magnetization; (b) …
It was reported a facile strategy to fabricate magnetite (Fe3O4) single-crystal particles with critical single-domain size by employing graphene oxide (GO) sheets as template. In this method, the small-sized Fe2O3 nanoparticles were first synthesized, and then low-temperature annealing under H2 would convert them into large-sized Fe3O4 single-crystal …
Stable remanent magnetization of magnetofossils is carried by single-domain [12, 13] and exceptionally [14] pseudo-single-domain magnetite, which, due to the chemical composition and shape of ...