... of its distribution over the tetrahedral and octahedral sites ( Henderson et al. 2007 ). Because L -edge XAS probes the empty d -orbitals of Fe and because of spin selectivity of X-ray magnetic circular dichroism (XMCD), these latter techniques can easily discriminate between Fe 2+ and Fe 3+ as well...

...Liao Chang; Richard A.D. Pattrick; Gerrit van der Laan; Victoria S. Coker; Andrew P. Roberts Abstract Greigite (Fe 3 S 4 ), a widely occurring iron thiospinel, was investigated using soft X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD). XAS and XMCD spectra were...

...-ulvöspinel (Fe 3 O 4 -Fe 2 TiO 4 ) solid-solution series was determined using Fe L 2,3 -edge X-ray magnetic circular dichroism (XMCD) coupled with electron microprobe and chemical analysis, Ti L 2,3 -edge and Fe K -edge X-ray absorption spectroscopy (XAS), and unit-cell parameters. Microprobe analyses, cell...

... to chemically similar phases that show different physical characteristics. We compare, for the first time, magnetite produced by these three different methods using X-ray magnetic circular dichroism (XMCD), a synchrotron radiation based technique able to determine the site occupancy of Fe cations in the ferrite...

... spectroscopic techniques of L 2,3 X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD). By comparing XMCD data with calculated spectra, the site occupancies of the Fe cations have been determined. From the analysis of natural ferrite spinels with formulae very close to that of pure...

...Richard A. D. PATTRICK; Gerrit VAN DER LAAN; C. Michael B. HENDERSON; Pieter KUIPER; Esther DUDZIK; David J. VAUGHAN Abstract X-ray magnetic circular dichroism (XMCD) is an element-, site- and symmetry-selective spectroscopic technique that has the potential to provide quantitative information...

...W. Alan Runciman; Marshall Marc Abstract Magnetic circular dichroism (MCD), which has been used for the study of paramagnetic ions in crystals, is now applied to minerals as a technique complementary to optical absorption. Two garnets from the pyrope-almandine series have been studied by both...

...P. F. Schofield; G. van der Laan; C. M. B. Henderson; G. Cressey The Fe 2p X-ray absorption spectra of single crystal gillespite, BaFeSi 4 O 10 , show a strong linear dichroism, i.e. a large difference in the absorption when measured with the polarization of the X-rays either parallel...

... from X-ray magnetic circular dichroism analysis revealed the magnetite to contain the V in the Fe(III) O h site, predominately as V(III) but always with a component of V(VI), present a consistent V(IV)/V(III) ratio in the range 0.28 to 0.33. The bacteriogenic production of V-doped magnetite...

... for these materials have a narrow single peak at 707.7 eV and the resulting main X-ray magnetic circular dichroism (XMCD) has the same sign at 708.75 eV. All XMCD spectra also have a broad positive feature at 711 eV, a characteristic of covalent mixing. The greigite XMCD spectra contrast with the three clearly...

.... This was done at ambient temperatures through the dissimilatory reduction of Fe 3+ -oxyhydroxides containing the appropriate substitutional cations. A combination of L -edge and K -edge X-ray absorption spectroscopy (XAS) and L -edge X-ray magnetic circular dichroism (XMCD) was used to determine the site...

...Claire Carvallo; Philippe Sainctavit; Marie-Anne Arrio; Nicolas Menguy; Yuheng Wang; Georges Ona-Nguema; Sandrine Brice-Profeta Abstract X-ray magnetic circular dichroism (XMCD) experiments were carried out to compare the Fe 2+ / Fe 3+ ratio in nanomagnetite chemically produced from lepidocrocite...

... of fluorohectorite, which has the highest layer charge, and exhibited dichroism. Models for the orientation of MB cations on a clay surface were proposed based on MB orientation models previously reported, and compared with the basal spacings determined by X-ray diffraction. In this work, polarized spectroscopy...

...)(330,2.0.14). The refractive indices are ω = 1.753, ε = 1.740; the mineral shows no dichroism and is colorless in thin fragments; streak = white; H = 4. It shows no fluorescence or phosphorescence under UV radiation and does not cathodeluminesce. The name is for Okanogan County, Washington. Copyright © 1980...

...K. Nassau; B. E. Prescott Abstract The “anomalous pleochroism” of Tsinober is observed in all irradiated synthetic quartz grown on minor rhombohedron seeds. This phenomenon was reexamined, using the absorption dichroism of the ordinary ray in basal sections for detailed study. The anisotropy...