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Concept

Hématite

Publications associées (30)

Spin wave dispersion of ultra-low damping hematite (α-Fe2O3) at GHz frequencies

Dirk Grundler, Mohammad Hamdi, Ferdinand Rémy Hynek Posva

Raw data associated to the manuscript ‘’Spin wave dispersion of ultra-low damping hematite (α-Fe2O3) at GHz frequencies‘’, Physical Review Materials 7, 054407(2023); doi: 10.1103/PhysRevMaterials.7.054407 Information about file fo ...

Zenodo2023

Spin wave dispersion of ultra-low damping hematite ( α−Fe2O3 ) at GHz frequencies

Dirk Grundler, Mohammad Hamdi, Ferdinand Rémy Hynek Posva

Low magnetic damping and high group velocity of spin waves (SWs) or magnons are two crucial parameters for functional magnonic devices. Magnonics research on signal processing and wave-based computation at GHz frequencies focused on the artificial ferrimag ...

2023

Photoelectrochemical Oxygen Evolution on Mesoporous Hematite Films Prepared from Maghemite Nanoparticles

Michael Graetzel, Shaik Mohammed Zakeeruddin

Iron oxides, especially hematite (alpha-Fe2O3), a are promising materials for applications in photoelectrochemical cells and photo-redox catalysis. However, realizing high-performance hematite photoanodes via an environmentally-friendly route remains a gre ...

2022

Oxidation of pyrite (FeS2) and troilite (FeS) impurities in kaolinitic clays after calcination

Karen Scrivener, Franco Alberto Zunino Sommariva

Valorisation of locally available clays for producing blended cements is crucial for a widespread adoption of sustainable binders incorporating these materials. In some places, clays can be intermixed with small amounts of iron sulfides, which could eventu ...

SPRINGER2022

Antiferromagnetic resonance in a-Fe2O3 up to its Neel temperature

Jean-Philippe Ansermet, Haiming Yu, Marcin Bialek

Hematite (alpha-Fe2O3) is an antiferromagnetic material with a very low spin damping and high Neel temperature. The temperature dependence of the antiferromagnetic resonance in a bulk single crystal of hematite was characterized from room temperature up to ...

AIP Publishing2022

Surface-induced reversal of a phase transformation for the synthesis of epsilon-Fe2O3 nanoparticles with high coercivity

Irena Markovic

A metastable 8-polymorph of iron(III) oxide (epsilon-Fe2O3) is a very attractive material from the technological, engineering, and scientific points of view. In comparison with other iron oxides, it is characterized by unusual magnetic properties and a gia ...

PERGAMON-ELSEVIER SCIENCE LTD2020

Grain morphology reconstruction of crystalline materials from Laue three-dimensional neutron diffraction tomography

Marina Garcia Gonzalez

The macroscopic properties of advanced engineering and functional materials are highly dependent on their overall grain orientation distribution, size, and morphology. Here we present Laue 3D neutron diffraction tomography providing reconstructions of the ...

Nature Research2020

Structural characterization and magnetic properties of chromium jarosite KCr3(OD)(6)(SO4)(2)

Sofie Janas

Potassium chromium jarosite, KCr3(OH)(6)(SO4)(2) (Cr-jarosite), is considered a promising candidate to display spin liquid behavior due to the strong magnetic frustration imposed by the crystal structure. However, the ground state magnetic properties have ...

ROYAL SOC CHEMISTRY2020

In situ observation of picosecond polaron self-localisation in alpha-Fe2O3 photoelectrochemical cells

Michael Graetzel, Ludmilla Steier

Hematite (alpha-Fe2O3) is the most studied artificial oxygen-evolving photo-anode and yet its efficiency limitations and their origin remain unknown. A sub-picosecond reorganisation of the hematite structure has been proposed as the mechanism which dictate ...

Springer2019

Low Fe(II) Concentrations Catalyze the Dissolution of Various Fe(III) (hydr)oxide Minerals in the Presence of Diverse Ligands and over a Broad pH Range

Janet Gordon Hering

Dissolution of Fe(III) (hydr)oxide minerals by siderophores (i.e., Fe-specific, biogenic ligands) is an important step in Fe acquisition in environments where Fe availability is low. The observed coexudation of reductants and ligands has raised the questio ...

AMER CHEMICAL SOC2019

Contaminant loading and competitive access of Pb, Zn and Mn(III) to vacancy sites in biogenic MnO2

Louise Helene Soegaard Jensen

The scavenging properties of MnO2 are largely attributed to sorption on layer vacancy sites. However, co-occurrence of Mn(II, III) with MnO2 can change mineral reactivity by modifying its Mn(III) content or number of free vacancy sites. These processes are ...

2018

Atomically Altered Hematite for Highly Efficient Perovskite Tandem Water-Splitting Devices

Michael Graetzel, Shaik Mohammed Zakeeruddin, Chenyi Yi

Photoelectrochemical (PEC) cells are attractive for storing solar energy in chemical bonds through cleaving of water into oxygen and hydrogen. Although hematite (alpha-Fe2O3) is a promising photoanode material owing to its chemical stability, suitable band ...

Wiley-VCH Verlag Berlin2017

Defects on surface and interface for photoelectrochemical properties of hematite photoanodes

Yelin Hu

Hydrogen is a highly versatile fuel that may become one of the key solutions to face our future energy challenges. Among all these methods for hydrogen production, solar water splitting offers possible advantages regarding components integration, stability ...

EPFL2017

Anisotropic magnetic polymer nanocomposite with self-assembled chains of titania-coated magnetite nanoparticles

Yves Leterrier, Tommaso Nardi

An anisotropic magnetic nanocomposite has been prepared by incorporating magnetite nanoparticles (average size: 19nm) in titania (TiO2) particles with a typical size of about 100nm, which are sub- sequently dispersed in a liquid epoxy monomer cured under a ...

Elsevier Science Bv2016

Light trapping in hematite-coated transparent particles for solar fuel generation

Ali Dabirian

Hematite (alpha-Fe2O3), due to its abundance and low-cost, is an attractive compound for photoelectrochemical splitting of water to produce hydrogen. However, one major obstacle preventing hematite from achieving the target efficiencies comprises its signi ...

Royal Soc Chemistry2015

Low-Temperature Atomic Layer Deposition of Crystalline and Photoactive Ultrathin Hematite Films for Solar Water Splitting

Michael Graetzel, Jingshan Luo, Matthew Thomas Mayer, Marcel Roland Schreier, Ludmilla Steier

We developed a low-temperature atomic layer deposition route to deposit phase pure and crystalline hematite (alpha-Fe2O3) films at 230 degrees C without the need for postannealing. Homogenous and conformal deposition with good aspect ratio coverage was dem ...

American Chemical Society2015

Cellular magnetic resonance with iron oxide nanoparticles: long-term persistence of SPIO signal in the CNS after transplanted cell death

Michele De Palma, Mario Leonardo Squadrito, Chiara Cianciaruso

Aim: To study the specificity of cellular MRI based on superparamagnetic iron oxide particles (SPIOs), especially within the CNS. Materials & methods: A microglial cell line was engineered for the expression of a suicide gene, the receptor of diphtheria to ...

Future Medicine Ltd2014

On the Texturing and Nanostructuring of Iron Oxide Photoanodes for Solar Water Splitting

Maurin Cornuz

The world needs to think about the after fossil fuel era and while the sun baths the earth with a tremendous amount of energy, man must learn how to harvest and store it in order to dispose of a continuous supply meeting his needs. Water photo-electrolysis ...

EPFL2013

The influence of pH on iron speciation in podzol extracts: Iron complexes with natural organic matter, and iron mineral nanoparticles

The quantities of natural organic matter (NOM) and associated iron (Fe) in soil extracts are known to increase with increasing extractant pH. However, it was unclear how the extraction pH affects Fe speciation for particles below 30 nm. We used flow field- ...

Elsevier Science Bv2013

Facile fabrication of tin-doped hematite photoelectrodes - effect of doping on magnetic properties and performance for light-induced water splitting

Michael Graetzel, Kevin Sivula

We present a new, easily scalable method for the deposition of nanocrystalline hematite photoelectrodes based on the spin-coating of a mixed solution containing tin(II) and iron(III) chlorides followed by thermal treatment. Our facile approach does not req ...

Royal Society of Chemistry2012