Al‐for‐Fe substitution in hematite: the effect of low Al concentrations in the Raman spectrum of Fe<sub>2</sub>O<sub>3</sub>

Zoppi, Angela; Lofrumento, Cristiana; Castellucci, E.; Sciau, Ph.

doi:10.1002/jrs.1811

Cited by 117 publications

(85 citation statements)

References 15 publications

(25 reference statements)

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“…This is in agreement with the experimental data of Mironova-Ulmane et al [9] and Cazzanelli et al [10]. Dussan-Devia et al [24] [25] and McCarty [26]. It must be noted, that our numerical calculations are made with model parameters, which are not fitted from experimental data, and we have taken into account only that J d and R d in the defected shells are greater or smaller compared to the parameters in the undefected shells due to different strain effects.…”

supporting

confidence: 93%

Spin–phonon interaction effects in pure and ion‐doped NiO nanoparticles

Wesselinowa

Apostolov

2010

Physica Status Solidi (b)

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Based on the Heisenberg model including spin-phonon interaction and using a Green's function technique we have studied the size and transition metal doping effects on the phonon properties of antiferromagnetic NiO nanoparticles. The phonon frequency decreases whereas the phonon damping increases with decreasing of particle size. We have shown that a close correlation exists between microstructural features, the different radii of the dopants, leading to different stress and different spin-phonon interaction, and the phonon properties of the nanoparticles. In dependence of the radii of the doped ions we obtain a decrease or increase of the phonon energy with increasing doping concentration. The phonon damping is always greater compared to the undoped case. Our theory can be applied to all antiferromagnetic nanoparticles.

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supporting

confidence: 93%

Spin–phonon interaction effects in pure and ion‐doped NiO nanoparticles

Wesselinowa

Apostolov

2010

Physica Status Solidi (b)

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“…[42 -45] Also trace iron is a known to be present in many Chinese glazes, even some that appear whitish (Ref. [41], p. 165)…”

Section: Discussionmentioning

confidence: 99%

Pure component Raman spectral reconstruction from glazed and unglazed Yuan, Ming, and Qing shards: a combined Raman microscopy and BTEM study

Widjaja

Lim

et al. 2011

J Raman Spectroscopy

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Raman mapping measurements were performed on the glazed and unglazed surfaces of shards excavated from Yuan, Ming, and Qing dynasty strata. A number of areas on each surface were chosen. Circa 21 × 21 pixels were measured for each area using both 514 and 785-nm laser as the Raman excitation. Data were collected from 100-3600 cm −1 . Many sets of spectra exhibited very intense fluorescence. In spite of the intense fluorescence, the resulting sets of spectra were collated and analyzed together using the band-target entropy minimization (BTEM) algorithm. Pure component spectral estimates of many of the major components were achieved, without the use of any a priori information such as spectral libraries. These include α-silica quartz, carbon, anatase, cobalt oxides, hematite, glassy silicate, and lanthanide complexes. In addition, two further unidentified pure component spectra A and B were recovered as well as an interference pattern due to the microscopic texture of the shards (associated with small particle/thin layer domains). The carbon was primarily present in elemental form, i.e. mixture of amorphous and graphitic (unordered and ordered domains); however there is an evidence of some partial oxidation, i.e. formation of carboxylates. The interference patterns and the lanthanide complexes were only observed when using the longer wavelength red laser. The cobalt oxides and the anatase were only observed when using the green laser. In summary, the combination of Raman microscopy and BTEM has allowed the enumeration of many of the underlying spectral patterns present and hence unambiguous identification of the major individual components present in the archaeological samples. This approach would appear applicable to other classes of archaeological materials as well. Limitations and extensions of the present approach are discussed.

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“…29 -31 It has recently also been illustrated that doping with aluminium broadens and shifts most bands in the haematite Raman spectrum to lower wavenumbers, which might be another explanation for the existence of this second spectrum. 32,33 The origin of the band at 1314 cm 1 has previously been attributed to a two magnon scattering process, but later work support a resonance-enhanced two-phonon process with the IR active band at 658 cm 1 as fundamental. 28,34 Interestingly, although this band has shifted downwards to 1303 cm 1 , the band at 658 cm 1 is still in the same position.…”

Section: Red Pigment On Shardmentioning

confidence: 98%

The first Raman spectroscopic study of San rock art in the Ukhahlamba Drakensberg Park, South Africa

Prinsloo

Barnard

Meiklejohn

et al. 2008

J Raman Spectroscopy

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San rock art sites are found throughout southern Africa; unfortunately this unique heritage is rapidly being lost through natural weathering processes, which have been the focus of various studies conducted in the uKhahlamba Drakensberg Park since 1992. It has recently been shown that the ability of Raman spectroscopy to identify salts on rock faces on a micro, as well as nano scale, can make a contribution to these projects.In order to test the feasibility of undertaking on-site analyses, a small rock fragment with red and white pigments still attached, which had weathered off the rock face, was analysed with Raman spectroscopy under laboratory conditions, using a Dilor XY Raman instrument and a DeltaNu Inspector Raman portable instrument. A small sample of black pigment (<1 mm 2 ), collected from a badly deteriorated painting and a few relevant samples collected on site, were analysed as well. It was possible to identify most of the inorganic pigments and minerals detected with previous XRD and EDX measurements including whewellite and weddellite coatings, which could be a tool for carbon dating purposes. Two carotenoid pigments were detected for the first time in San rock art pigments. Animal fat was also observed for the first time on both red and white pigments, on the rock face adjacent to the paintings and in highest concentrations on the back of the rock fragment. The spectra quality makes successful on-site measurements a good prospect.

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Al‐for‐Fe substitution in hematite: the effect of low Al concentrations in the Raman spectrum of Fe₂O₃

Cited by 117 publications

References 15 publications

Spin–phonon interaction effects in pure and ion‐doped NiO nanoparticles

Spin–phonon interaction effects in pure and ion‐doped NiO nanoparticles

Pure component Raman spectral reconstruction from glazed and unglazed Yuan, Ming, and Qing shards: a combined Raman microscopy and BTEM study

The first Raman spectroscopic study of San rock art in the Ukhahlamba Drakensberg Park, South Africa

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Al‐for‐Fe substitution in hematite: the effect of low Al concentrations in the Raman spectrum of Fe2O3

Cited by 117 publications

References 15 publications

Spin–phonon interaction effects in pure and ion‐doped NiO nanoparticles

Spin–phonon interaction effects in pure and ion‐doped NiO nanoparticles

Pure component Raman spectral reconstruction from glazed and unglazed Yuan, Ming, and Qing shards: a combined Raman microscopy and BTEM study

The first Raman spectroscopic study of San rock art in the Ukhahlamba Drakensberg Park, South Africa

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Al‐for‐Fe substitution in hematite: the effect of low Al concentrations in the Raman spectrum of Fe₂O₃