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2 edition of Crystallographic studies of magnetite and titanomaghemite. found in the catalog.

Crystallographic studies of magnetite and titanomaghemite.

Stephen Collyer

Crystallographic studies of magnetite and titanomaghemite.

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Published by Aston University. Department of Geological Sciences in Birmingham .
Written in English


Edition Notes

Thesis (PhD) - Aston University, 1986.

ID Numbers
Open LibraryOL13775376M

The study, "High-Throughput Calculations of Magnetic Topological Materials" by Yuanfeng Xu, Luis Elcoro, Zhida Song, Benjamin J. Wieder, M. G. Vergniory, Nicolas Regnault, Yulin Chen, Claudia. Antiferromagnets and ferrimagnets show ordered arrangements of magnetic moments in a crystal structure involving two (or more) sub-lattices with antiparallel spin alignments and stabilized by indirect exchange mechanisms, often involving intervening oxygen ions. Antiferromagnets, where the contributions from the two sub-lattices are equal in magnitude but opposite in direction, show a.


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Crystallographic studies of magnetite and titanomaghemite. by Stephen Collyer Download PDF EPUB FB2

Systematic magnetic and crystallographic studies were made on 57 titanomaghemite samples produced from sintered titanomagnetites with x values of, and Curie temperature and lattice parameter values are often significantly different from results of previous studies (Ozima and Sakamoto, ; Readman and O'Reilly, ; Nishitani, ), particularly for x values of 0.

Crystallographic studies of magnetite and titanomaghemite Author: A study of Friedel related pairs of X-ray intensities shows that Friedel's law is violated in magnetite, further confirming that the space group is non-centrosymmetrical. The crystal structure of a natural titanomaghemite was determined by a combination of X-ray.

Three titanomagnetite samples, of composition x=,and (where x is the ulvöspinel molecular fraction), were oxidized according to the method of Sakamoto et al., namely, wetgrinding followed by heating to –°C.

Like the samples of Sakamoto et al., our samples showed reversal of saturation magnetization during alteration of titanomagnetite to by: Helgason, Titanomaghemite in Icelandic basalt: possible clues for the strongly magnetic phase in Martian soil and dust, Planetary and Space Science, /S(01)X, 50, Cited by: oxidized Ti-rich magnetite or titanomaghemite, but not.

identical to those for hematite or magnetite (Shebanova & Lazor() Studies of the crystal-structure and crystal. We have shown that synchrotron 2‐dimensional X‐ray diffraction is a powerful tool to study the crystallographic orientation of magnetosomes and the texture of magnetosome chains in magnetotactic bacteria.

From our analysis, we can draw three main conclusions on the biological organization of magnetic nanoparticles Crystallographic studies of magnetite and titanomaghemite.

book 1D. Crystallographic and magnetic properties of the compound MnAs P are studied in the temperature range from to °K. X-ray diffraction studies reveal this compound deforms at °K with decreasing temperature from hexagonal B8 1 into orthorhombic B31 structure, as pointed out by Goodenough et of the orthorhombic deformation δ (shown in the text) in this case is first.

Study of the Sarmiento ophiolite magnetic minerals: Contribution to the reconnaissance of a metamorphic overprint. In 6th International Symposium on Andean Geodynamics (ISAGBarcelona), Extended Abstracts (pp.

General Magnetite Information: Chemical Formula: Fe++Fe+++2O4: Composition: Molecular Weight = gm Iron % Fe % FeO / % Fe 2 O 3:. The following article is from The Great Soviet Encyclopedia (). It might be outdated or ideologically biased. Titanomagnetite a mineral of the complex oxide class; an intermediate member of the isomorphous series of solid solutions of magnetite (FeFe2O4), ulvospinel (Fe2TiO4), and magnesian ulvospinel (Mg2TiO4).

Titanomagnetite is also the name for. Bosi F, Hålenius U, Skogby H () Crystal chemistry of the magnetite-ulvöspinel series, American Mineralogist, 94, Gotic M, Koscec G, Music S () Study of the reduction and reoxidation of substoichiometric magnetite, Journal of Molecular Structure, Magnetite (Fe3O4) is a well-recognized petrogenetic indicator and is a common accessory mineral in many ore deposits and their host rocks.

Recent years have seen an increased interest in the use of hydrothermal magnetite for provenance studies and as a pathfinder for mineral exploration. A number of studies have investigated how specific formation conditions are reflected in the composition of.

MAGNETIC AND CRYSTALLOGRAPHIC STUDIES OF SUBSTITUTED GADOLINIUM IRON GARNETS [Geller, S., et al] on *FREE* shipping on qualifying offers.

MAGNETIC AND CRYSTALLOGRAPHIC STUDIES OF SUBSTITUTED GADOLINIUM IRON GARNETSAuthor: et al Geller, S. The magnetic behavior of both 3α and the 3β/3γ/3δ system reflect an S = 1/2 paramagnet with weak antiferromagnetic coupling.

The reversible 3δ ↔ 3γ phase transition exhibits thermal hysteresis of 20 K. Below 50 K, the value of χ m T for 3δ approaches 0 emuKmol –1 consistent with formation of a gapped state with an S = 0 ground.

Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids (see crystal structure).The word "crystallography" is Crystallographic studies of magnetite and titanomaghemite. book from the Greek words crystallon "cold drop, frozen drop", with its meaning extending to all solids with some degree of transparency, and graphein "to write".

In Julythe United Nations recognised the importance of the. Book Description. Rare-earth intermetallics, also known as lanthanide elements, play an important role in the study of magnetic materials and the development of semi- and super-conducting materials.

This handbook provides an up-to-date compilation of crystallographic, physical, and magnetic data on rare-earth intermetallic compounds. Maghemite γ–Fe2O3 c Mineral Data Publishing, version 1 Crystal Data: Cubic, typically with a tetragonal supercell.

Point Group: n.d. Rarely as minute octahedral crystals, or acicular overgrowths; commonly as coatings on or replacements of. Abstract. Magnetite (Fe 3 O 4, ferrous–ferric oxide) is ubiquitous as the source of the magnetism of most biological magnetic gh a cation-deficient form of it, maghemite (γ- Fe 2 O 3), and impurity-substituted magnetite (titanomagnetite) have on occasion been identified in biomagnetic systems, magnetite continues to be the primary magnetic source in biology.

This study of the crystal structure, electronic structure, and magnetic properties of the ζ2-GaM (M = Cr, Mn or Fe) alloys is motivated by the recent reinvestigation of the crystallographic Al8Cr5 structure type of ζ2-GaMn. The isostructural compounds ζ2-GaFe and ζ2-GaCr have been refined using X-ray powder diffraction as well as neutron powder diffraction for ζ2-GaFe.

The revised value corresponds to +/wt% magnetite if the magnetic mineral is magnetite (using Js=92Am2/kg for pure magnetite, Fe3O4) or to +/ to +/wt% maghemite if the magnetic. X-ray crystallography (XRC) is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions.

By measuring the angles and intensities of these diffracted beams, a crystallographer can produce a three-dimensional picture of the density of electrons within the.

Nuclear magnetic resonance and crystallographic studies of chiral η 3-allyl palladium(II) complexes and asymmetric allylic alkylation of propenyl acetates E. Cesarotti, M. Grassi, L. Prati and F. Demartin, J. Chem. Soc., Dalton Trans., The chapters are extensively illustrated and deal with such topics as symmetry elements, operations and descriptors, symmetry guidelines, high-fidelity pseudosymmetry, crystallographic symmetry, molecular gears, and experimental techniques, including X-ray crystallography and NMR spectroscopy.

Here, we show a comprehensive transmission electron microscopy (TEM) study of magnetic and structural properties down to atomic scales on bullet-shaped magnetites produced by the uncultured strain MYR-1 belonging to the Nitrospirae phylum, a deeply branching phylogenetic MTB group.

We observed a multiple-step crystal growth of MYR-1 magnetite. Certainly a formal or semi-formal link with the solid-state NMR community is desirable’. Forearmed with this book, I would support that proposal. This book, I would also conclude, should be in the library of crystallographic laboratories, across all the disciplines.” (Crystallography Reviews, 14 February ).

By magnetic structures we refer to the mutual alignment of the magnetic moments of the atoms in a crystal and their overall alignment relative to the crystallographic axes.

Some indirect, tentative data on the magnetic structure of magnetic materials can be obtained from research on their magnetic, mechanical, thermal, and other properties. A comparative study of the crystallographic, magnetic and electrical properties of the Nd 1-x La x NiO 3- delta system.

J Blasco and J Garcia. Published 5 December • Journal of Physics: Condensed Matter, Volume 6, Number MAGNETIC METHOD The magnetic method exploits small variations in magnetic mineralogy (magnetic iron and iron-titanium oxide minerals, including magnetite, titanomagnetite, titanomaghemite, and titanohematite, and some iron sulfide minerals, including pyrrhotite and greigite) among rocks.

Measurements are made using fluxgate, proton-precession. Magnetite Properties. Magnetite is very easy to recognize because it’s one of the very few gemstones that get attracted to a common magnet.

It’s the most magnetic mineral that can be found, hence the name. It’s also known as Lodestone or Magnetic Hematite. It’s black-grey in color, but there are also magnetite stones that are grey and.

The crystal structure and magnetic properties of the compound Na 5 [Mn(L-tart) 2]12H 2 O (1, L-tart = L-tartrate) have been investigated over the pressure range – bulk modulus of 1 has been determined as (6) GPa, with a compression of the coordination spheres around the Na + ions observed.

1 is therefore relatively incompressible, helping it to retain its magnetic. The structure of magnetite. Fleet. Read article Similar articles. This is the first page of the article you requested.

Follow Acta Cryst. B: E-alerts: Twitter: The IUCr is a scientific union serving the interests of crystallographers and other scientists employing crystallographic methods.

mension for St. Vincent magnetite sample TI is 8' in reasonable agreement with the observed value and considerably lower than the value for pure magnetite. However, a further manner in which cell size of natural magnetite and titanomagnetite can be reduced is by partial oxidation to maghemite or titanomaghemite.

Titanomaghemite, an oxidized titanomagnetite having compositions near the TiFeO 3-Fe 2 O 3 join or even within the TiFe 2 O 5-TiFeO 3-Fe 2 O 3 triangular field in the system TiO 2-FeO-Fe 2 O 3, has been found in some Japanese igneous copically the mineral canlie distinguished from titanomagnetite by its bluish gray color in reflected light and the abundance of cracks.

Magnetite, also called lodestone, or magnetic iron ore, iron oxide mineral (FeFe 2 O 4, or Fe 3 O 4) that is the chief member of one of the series of the spinel (q.v.) ls in this series form black to brownish, metallic, moderately hard octahedrons and masses in igneous and metamorphic rocks and in granite pegmatites, stony meteorites, and high-temperature sulfide veins.

crystallographic computing; crystallographic nomenclature; crystallographic teaching; crystallography in art and cultural heritage; crystallography of materials; electron crystallography; high pressure; inorganic and mineral structures; international tables; journals; magnetic structures; mathematical and theoretical crystallography; neutron.

Jacobsite-Magnetite Series. Magnesioferrite-Magnetite Series. Magnetite is an important iron ore, along with hematite. Nanoinclusions of magnetite crystals cause the iridescence of Rainbow obsidian (Nadin, ).

Extremely thin layers of nm octahedral crystals of magnetite give some basalt surfaces an iridescent sheen (Nadin, ). Seafloor hydrothermal systems in the back-arc region of the Okinawa Trough have been viewed as a modern analogue to the Kuroko-type volcanogenic massive sulfide deposits.

Detection of magnetic signatures is widely utilized and assumed to facilitate the understanding of geological controls on hydrothermal system genesis. However, the magnetic properties of seafloor volcanic rocks are still. We report here on the characterization of the vacancy-ordered perovskite-type structure of BaFeO by means of combined Rietveld analysis of powder X-ray and neutron diffraction data.

The compound crystallizes in the monoclinic space group P21/c [a = (1) Å, b = (2) Å, c = (4) Å, β = (1)°, and Z = 28] containing seven crystallographically different iron atoms. Nanocrystals of magnetite (Fe 3 O 4) inside Gyr-old carbonate in Martian meteorite Allan Hills (ALH) contain a record of the ancient Martian magnetic field and possible evidence for fossil Martian life ().Two recent studies have advanced the claim that the magnetites were made by microorganisms.

Thomas-Keprta et al. used transmission electron microscopy (TEM) to study. For the book of poetry, see Crystallography (book). Crystallography (from the Greek words crystallon = cold drop / frozen drop, with its meaning extending to all solids with some degree of transparency, and graphein = write) is the experimental science of determining the arrangement of atoms in older usage, it is the scientific study of crystals.

ATHENA, ARTEMIS, HEPHAESTUS This software package is based on the IFEFFIT library of numerical and XAS algorithms. The programs described here are: (i) ATHENA, a program for XAS data processing, (ii) ARTEMIS, a program for EXAFS data analysis using theoretical standards from FEFF and (iii) HEPHAESTUS, a collection of beamline utilities based on tables of atomic absorption data.

For different applications, several chemical methods can be used to synthesize magnetic nanoparticles: co-precipitation, reverse micelles and micro-emulsion technology, sol-gel syntheses, sonochemical reactions, hydrothermal reactions, hydrolysis and thermolysis of precursors, flow injection syntheses, and electrospray syntheses [].The synthesis of superparamagnetic nanoparticles is a .We have compiled an electronic book entitled Magnetic Space Groups.3 This book presents tables of crystallographic properties ofthe reduced magnetic superfamilies of one- two-and three-dimensional space-group types, which we shall refer to simply as one- two- and three-dimensional magnetic .