Point defects and transport in haematite (Fe2O3-ε)

Dieckmann, R.

doi:10.1080/01418619308213994

Cited by 63 publications

(54 citation statements)

References 27 publications

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“…The deviation from stoichiometry is small (about e = 10 À5 at 1100°C) [125]. If water is incorporated in the oxide it would be expected to be as protons resulting in formation of the OH À ion.…”

Section: Iron Oxidesmentioning

confidence: 99%

The oxidation behaviour of metals and alloys at high temperatures in atmospheres containing water vapour: A review

Saunders

Monteiro

Rizzo

2008

Progress in Materials Science

551

248

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Section: Iron Oxidesmentioning

confidence: 99%

The oxidation behaviour of metals and alloys at high temperatures in atmospheres containing water vapour: A review

Saunders

Monteiro

Rizzo

2008

Progress in Materials Science

551

248

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“…Knowledge of point defects and diffusion in bulk α-Fe 2 O 3-ε was reviewed in 1993 by Dieckmann [168], who concluded that oxygen vacancies are the dominant defect between 1373 and 1573 K. The topic has been studied on several occasions since, both experimentally [169] and theoretically [170; 171]. Simultaneous measurements of 57 Fe and…”

Section: Defects and Diffusionmentioning

confidence: 99%

Iron oxide surfaces

Parkinson

2016

Surface Science Reports

488

463

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The current status of knowledge regarding the surfaces of the iron oxides, magnetite (Fe 3 O 4 ), maghemite (γ-Fe 2 O 3 ), hematite (α-Fe 2 O 3 ), and wüstite (Fe 1-x O) is reviewed. The paper starts with a summary of applications where iron oxide surfaces play a major role, including corrosion, catalysis, spintronics, magnetic nanoparticles (MNPs), biomedicine, photoelectrochemical water splitting and groundwater remediation. The bulk structure and properties are then briefly presented; each compound is based on a close-packed anion lattice, with a different distribution and oxidation state of the Fe cations in interstitial sites. The bulk defect chemistry is dominated by cation vacancies and interstitials (not oxygen vacancies) and this provides the context to understand iron oxide surfaces, which represent the front line in reduction and oxidation processes. The atomic-scale structure of the low-index surfaces of iron oxides is the major focus of this review. Fe 3 O 4 is the most studied iron oxide in surface science, primarily because its stability range corresponds nicely to the ultra-high vacuum environment, and because it is an electrical conductor, which makes it straightforward to study with the most commonly used surface science methods such as photoemission spectroscopies (XPS, UPS) and scanning tunneling microscopy (STM). The impact of the surfaces on the measurement of bulk properties such as magnetism, the Verwey transition and the (predicted) half-metallicity is discussed.The best understood iron oxide surface at present is probably Fe 3 O 4 (100); the structure is known with a high degree of precision and the major defects and properties are well characterised. A major factor in this is that a termination at the Fe oct -O plane can be reproducibly prepared by a variety of methods, as long as the surface is annealed in 10 Such straightforward preparation of a monophase termination is generally not the case for other iron oxide surfaces. All available evidence suggests the oft-studied (√2×√2)R45° reconstruction results from a rearrangement of the cation lattice in the outermost unit cell in which two octahedral cations are replaced by one tetrahedral interstitial, a motif conceptually similar to well-known Koch-Cohen defects in Fe (0001) is the most studied hematite surface, but 2 difficulties preparing stoichiometric surfaces under UHV conditions have hampered a definitive determination of the structure. There is evidence for at least three terminations: a bulk-like termination at the oxygen plane, a termination with half of the cation layer, and a termination with ferryl groups. When the surface is reduced the so-called "bi-phase" structure is formed, which eventually transforms to a Fe 3 O 4 (111)-like termination. The structure of the bi-phase surface is controversial; a largely accepted model of coexisting Fe 1-x O and α-Fe 2 O 3 (0001) islands was recently challenged and a new structure based on a thin film of Fe 3 O 4 (111) on α-Fe 2 O 3 (0001) was proposed. The merits of the compet...

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“…Hematite (α-Fe 2 O 3 ) is the oldest iron oxide and is widespread in rocks and soils. It is the most stable iron oxide under ambient condition and has significant scientific and technological importance [8]. The stability and semiconductor (n-type) properties of α-Fe 2 O 3 allow it to be used as a photocatalyst [9].…”

mentioning

confidence: 99%

Hydrothermal Novel Synthesis of Neck-structured Hyperthermia-suitable Magnetic (Fe3O4, γ-Fe2O3 and α-Fe2O3) Nanoparticles

et al. 2011

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Novel neck-structured Fe3O4, γ-Fe2O3 and α-Fe2O3 magnetic nanoparticles were successfully prepared by a modified hydrothermal method. Ferrous chloride tetrahydrate was solely used as a precursor for the novel nanomaterials. The X-ray diffractometric study revealed the purity of the nanomaterials thus synthesized. All of the products were characterized using a field-emission scanning electron microscope (FE-SEM) and a transmission electron microscope (TEM) for the particle size and morphology. Neck-structured particle morphology was observed for the first time in all of iron oxides with magnetic properties. The particle size observed was 50–60 nm. The synthesized nanomaterials showed excellent magnetization values when magnetic hysteresis loops were measured using a superconducting quantum interference device (SQUID). Moreover, the as-prepared magnetic nanoparticles suspensions showed significant temperature increments under an AC (alternating current) magnetic-field induction condition at room temperature which indicates the hyperthermia feasibility. Keywords: Magnetic materials; Neck-structured; Hyperthermia; Heat dissipation. © 2012 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. doi: http://dx.doi.org/10.3329/jsr.v4i1.8727J. Sci. Res. 4 (1), 99-107 (2012)

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Point defects and transport in haematite (Fe₂O_3-ε)

Cited by 63 publications

References 27 publications

The oxidation behaviour of metals and alloys at high temperatures in atmospheres containing water vapour: A review

The oxidation behaviour of metals and alloys at high temperatures in atmospheres containing water vapour: A review

Iron oxide surfaces

Hydrothermal Novel Synthesis of Neck-structured Hyperthermia-suitable Magnetic (Fe<sub>3</sub>O<sub>4</sub>, γ-Fe<sub>2</sub>O<sub>3</sub> and α-Fe<sub>2</sub>O<sub>3</sub>) Nanoparticles

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Point defects and transport in haematite (Fe2O3-ε)

Cited by 63 publications

References 27 publications

The oxidation behaviour of metals and alloys at high temperatures in atmospheres containing water vapour: A review

The oxidation behaviour of metals and alloys at high temperatures in atmospheres containing water vapour: A review

Iron oxide surfaces

Hydrothermal Novel Synthesis of Neck-structured Hyperthermia-suitable Magnetic (Fe<sub>3</sub>O<sub>4</sub>, &gamma;-Fe<sub>2</sub>O<sub>3</sub> and &alpha;-Fe<sub>2</sub>O<sub>3</sub>) Nanoparticles

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Point defects and transport in haematite (Fe₂O_3-ε)

Hydrothermal Novel Synthesis of Neck-structured Hyperthermia-suitable Magnetic (Fe<sub>3</sub>O<sub>4</sub>, γ-Fe<sub>2</sub>O<sub>3</sub> and α-Fe<sub>2</sub>O<sub>3</sub>) Nanoparticles