Magnetic Properties and Redox State of Impact Glasses: A Review and New Case Studies from Siberia

High velocity impacts produce melts that solidify as ejected or in-situ glasses. We provide a review of their peculiar magnetic properties, as well as a new detailed study of four glasses from Siberia: El’gygytgyn, Popigai, urengoites, and South-Ural glass (on a total of 24 different craters or strewn-fields). Two types of behavior appear: 1) purely paramagnetic with ferromagnetic impurities at most of the order of 10 ppm; this corresponds to the five tektite strewn-fields (including the new one from Belize), urengoites, and Darwin glass. Oxidation state, based in particular on X-ray spectroscopy, is mostly restricted to Fe2+; 2) variable and up to strong ferromagnetic component, up to the 1 wt % range, mostly due to substituted magnetite often in superparamagnetic state. Accordingly, bulk oxidation state is intermediate between Fe2+ and Fe3+, although metallic iron, hematite, and pyrrhotite are sometimes encountered. Various applications of these magnetic properties are reviewed in the field of paleomagnetism, magnetic anomalies, recognition of glass origin, and formation processes.

Download Full-text

Magnetic Properties of Ferrous Ferric Oxide Confined in Porous Silicon

Materials Science Forum ◽

10.4028/www.scientific.net/msf.663-665.1142 ◽

2010 ◽

Vol 663-665 ◽

pp. 1142-1145

Author(s):

Yuan Ming Huang ◽

Bao Gai Zhai ◽

Qing Lan Ma ◽

Ming Meng

Keyword(s):

Electron Microscopy ◽

Magnetic Properties ◽

Iron Oxide ◽

Porous Silicon ◽

Ferrous Iron ◽

Silicon Film ◽

X Ray ◽

Loop Measurement ◽

Scanning Electron

During the chemical synthesis nanometer-sized particles of ferrous iron oxide were in situ infiltrated into the mesopores in a porous silicon film. The microstructures of porous silicon and the magnetic properties of the nanometer-sized particles of the ferrous iron oxide were characterized with scanning electron microscopy, X-ray diffractometry, and the hysteresis loop measurement, respectively. Our results have demonstrated that the magnetic properties of the nanometer-sized Fe3O4 particles can be dramatically modified when they are confined into the mesopores of the porous silicon film.

Download Full-text

Insights into sulfur poisoning and regeneration of Cu-SSZ-13 catalysts: In situ Cu and S K-edge XAS studies

Catalysis Science & Technology ◽

10.1039/d1cy00975c ◽

2021 ◽

Author(s):

Vitaly Mesilov ◽

Sandra Dahlin ◽

Susanna Liljegren Bergman ◽

Peter Sams Hammershøi ◽

Shibo Xi ◽

...

Keyword(s):

Selective Catalytic Reduction ◽

Oxidation State ◽

Absorption Spectroscopy ◽

Catalytic Reduction ◽

Sulfur Poisoning ◽

X Ray ◽

Scr Catalysts ◽

X Ray Absorption

In situ Cu and S K-edge X-ray absorption spectroscopy (XAS) was used for the investigation of sulfur-poisoned and regenerated Cu-SSZ-13 selective catalytic reduction (SCR) catalysts. Sulfur in the oxidation state...

Download Full-text

In Situ X-Ray Diffraction and In Situ X-Ray Absorption Spectroscopy for Investigation of Intercalation Batteries: Application to the Alkaline H+/γ-MnO2 system.

MRS Proceedings ◽

10.1557/proc-210-387 ◽

1990 ◽

Vol 210 ◽

Cited By ~ 2

Author(s):

C. Lévy-Clèment ◽

C. Mondoloni ◽

C. Godart ◽

R. Cortès

Keyword(s):

Charge Transfer ◽

Oxidation State ◽

Absorption Spectroscopy ◽

Crystallographic Structure ◽

X Ray Diffraction ◽

Alkaline Batteries ◽

X Ray ◽

In Situ Techniques ◽

X Ray Absorption

AbstractThis paper presents applications of in situ X-ray diffraction and absorption techniques to the study of H+/MnO2 alkaline batteries. The two complementary in situ techniques are described. Investigation of the electrochemical insertion and deinsertion of H+ has been made through its influence on the evolution of the crystallographic structure of γ-MnO2, while investigation of the transfer of e has been undertaken through the variation of the oxidation state of the manganese during the discharging and charging process of a battery. New insights in the understanding of the mechanisms of proton insertion and charge transfer into γ-MnO2 are discussed.

Download Full-text

Epitaxial Co-Cu Superlattices

MRS Proceedings ◽

10.1557/proc-231-235 ◽

1991 ◽

Vol 231 ◽

Author(s):

Elizabeth Schuler ◽

Sezai Elagoz ◽

William Vavra ◽

Frank Lamelas ◽

Hui David He ◽

...

Keyword(s):

Magnetic Properties ◽

Molecular Beam Epitaxy ◽

Layer Thickness ◽

Molecular Beam ◽

Antiferromagnetic Coupling ◽

Competing Interactions ◽

X Ray ◽

X Ray Scattering ◽

Complex Spin

AbstractWe describe measurements on the magnetic properties of Co-Cu superlattices in which the Co layer thickness was fixed at 20 Å and the Cu thickness was varied from 4 Å to 24 Å. The samples were grown on Ge-buffered (110) GaAs by molecular beam epitaxy. X-ray scattering and in-situ RHEED indicate that the multilayers are oriented in the (111) direction with the Co layers stacked in an fcc arrangement. Our interest in this series of samples lies in their unusual hysteresis curves which show distinct transitions. We have found that the appearance of these transitions is directly related to the Cu thickness, indicating the presence of complex spin configurations as a consequence of competing interactions. The results are not consistent with a simple RKKY antiferromagnetic coupling.

Download Full-text

Preparation of LaFeO3 particles by sol-gel technology

Journal of Materials Research ◽

10.1557/jmr.1998.0058 ◽

1998 ◽

Vol 13 (2) ◽

pp. 451-456 ◽

Cited By ~ 39

Author(s):

C. Vázquez-Vázquez ◽

P. Kögerler ◽

M. A. López-Quintela ◽

R. D. Sánchez ◽

J. Rivas

Keyword(s):

Particle Size ◽

Magnetic Properties ◽

Infrared Spectroscopy ◽

Sol Gel ◽

Diffraction Peak ◽

Gel Formation ◽

X Ray Diffraction ◽

X Ray ◽

Ferromagnetic Component ◽

Peak Broadening

The study of submicroscopic particles in already known systems has resulted in a renewed interest due to the large differences found in their properties when the particle size is reduced, and because of possible new technological applications. In this work we report the preparation of LaFeO3 particles by the sol-gel route, starting from a solution of the corresponding metallic nitrates and using urea as gelificant agent. Gels were decomposed at 200 °C and calcined 3 h at several temperatures, T, in the range 250–1000 °C. The samples were structurally characterized by x-ray diffraction (XRD) showing that the orthoferrite crystallizes at T as low as 315 °C. From the x-ray diffraction peak broadening, the particle size was determined. The size increases from 60 to 300 nm as the calcination T increases. Infrared spectroscopy was used to characterize gels and calcined samples. From these studies a mechanism for the gel formation is proposed. Study of the magnetic properties of LaFeO3 particles shows the presence of a ferromagnetic component which diminishes as the calcination temperature increases, vanishing at T = 1000 °C.

Download Full-text

A compact furnace for in situ X-ray absorption spectroscopy: design, fabrication and study of cationic oxidation states in Pr6O11 and NiO

Journal of Synchrotron Radiation ◽

10.1107/s1600577520015696 ◽

2021 ◽

Vol 28 (2) ◽

pp. 455-460

Author(s):

Suchinda Sattayaporn ◽

Somboonsup Rodporn ◽

Pinit Kidkhunthod ◽

Narong Chanlek ◽

Chutarat Yonchai ◽

...

Keyword(s):

Oxidation State ◽

Absorption Spectroscopy ◽

Heating Temperature ◽

Reduction Process ◽

Oxidation States ◽

Quartz Tube ◽

Edge Structure ◽

X Ray ◽

X Ray Absorption

A well designed compact furnace has been designed for in situ X-ray absorption spectroscopy (XAS). It enables various heat ramps from 300 K to 1473 K. The furnace consists of heaters, a quartz tube, a circulated refrigerator and a power controller. It can generate ohmic heating via an induction process with tantalum filaments. The maximum heating rate exceeds 20 K min−1. A quartz tube with gas feedthroughs allows the mixing of gases and adjustment of the flow rate. The use of this compact furnace allows in situ XAS investigations to be carried out in transmission or fluorescence modes under controlled temperature and atmosphere. Moreover, the furnace is compact, light and well compatible to XAS. The furnace was used to study cationic oxidation states in Pr6O11 and NiO compounds under elevated temperature and reduced atmosphere using the in situ X-ray absorption near-edge structure (XANES) technique at beamline 5.2 SUT-NANOTEC-SLRI of the Synchrotron Light Research Institute, Thailand. At room temperature, Pr6O11 contains a mixture of Pr3+ and Pr4+ cations, resulting in an average oxidation state of +3.67. In situ XANES spectra of Pr (L 3-edge) show that the oxidation state of Pr4+ cations was totally reduced to +3.00 at 1273 K under H2 atmosphere. Considering NiO, Ni2+ species were present under ambient conditions. At 573 K, the reduction process of Ni2+ occurred. The Ni0/Ni2+ ratio increased linearly with respect to the heating temperature. Finally, the reduction process of Ni2+ was completely finished at 770 K.

Download Full-text

Quantitative determination of the oxidation state of iron in biotite using X-ray photoelectron spectroscopy: II. In situ analyses

Geochimica et Cosmochimica Acta ◽

10.1016/s0016-7037(97)00264-0 ◽

1997 ◽

Vol 61 (21) ◽

pp. 4531-4537 ◽

Cited By ~ 8

Author(s):

Stuart P. Raeburn ◽

Eugene S. Ilton ◽

David R. Veblen

Keyword(s):

Quantitative Determination ◽

Oxidation State ◽

Photoelectron Spectroscopy ◽

X Ray

Download Full-text

Investigation of Magnetic Properties and Nanostructure of Fe2.75Mn0.25O4@ PANI Materials and their Potential as the Magnetic Ink

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.855.308 ◽

2020 ◽

Vol 855 ◽

pp. 308-314

Author(s):

Nadiya Miftachul Chusna ◽

Sunaryono ◽

Yunan Amza Muhammad ◽

Rosabiela Irfa Andin ◽

Ahmad Taufiq

Keyword(s):

Magnetic Properties ◽

Crystal Size ◽

In Situ Polymerization ◽

Xrd Analysis ◽

Hysteresis Curve ◽

Vibrating Sample Magnetometer ◽

X Ray Diffraction ◽

X Ray ◽

Polymerization Method

The Fe2.75Mn0.25O4 nanoparticles were successfully synthesized by using the coprecipitation method, while the Fe2.75Mn0.25O4@PANI materials were successfully fabricated by using the in situ polymerization method. This research aimed to investigate the magnetic properties and nanostructure of the Fe2.75Mn0.25O4 nanoparticles and Fe2.75Mn0.25O4@PANI materials. Some characterizations of the samples were successfully carried out by using X-Ray Diffraction (XRD) instruments, Fourier Transform Infrared (FTIR), and Vibrating Sample Magnetometer (VSM) each of which was conducted to characterize the crystal structure, functional groups, morphology, and the magnetic properties of the materials. The XRD analysis results showed that the Fe2.75Mn0.25O4@PANI materials had a crystal size of 8.09 nm. Meanwhile, the FTIR spectrum represented vibrations due to the atomic bonds that made up the Fe2.75Mn0.25O4@PANI materials. Furthermore, the hysteresis curve from the VSM characterization results showed that the Fe2.75Mn0.25O4@PANI material saturation magnetization value was around 2.85 emus/g. From those characterization results, the Fe2.75Mn0.25O4@PANI materials are very potential to be applied as magnetic ink

Download Full-text