Magnetic properties of calcium-silicates (diopside and gehlenite) doped with iron (III)

Nöller, Renate; Knöll, Heinz-Dieter

doi:10.1016/0038-1098(83)90552-5

Cited by 15 publications

(4 citation statements)

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“…In wollastonite this does not alter the magnetic susceptibility, but in gehlenite the incorporation of Fe can increase the magnetic susceptibility drastically. As shown by Nöller and Knoll (1983), the magnetic susceptibility of Fegehlenite can reach 36.5 Â 10 À3 (in emu), which is in agreement with the measured susceptibility for the test samples in this study. The mineralogical origin for the change in magnetic susceptibility in the case of our test series is therefore thought to be the gradual formation of Fe-gehlenite, possibly augmented by small amounts of neoformation hematite.…”

Section: Validating the Methods Through An Experimental Approachsupporting

confidence: 92%

Pottery firing temperatures: a new method for determining the firing temperature of ceramics and burnt clay

Rasmussen

Fuente

Bond

et al. 2012

Journal of Archaeological Science

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a b s t r a c tA new method for determining the maximum firing temperature of ceramics and burnt clay is presented. The technique relies on measuring the magnetic susceptibility on a step-wise re-fired sample. The validity of the method has been tested by determining firing temperatures of two sets of clay samples fired at temperatures ranging from 400 to 1000 C. Aliquots of the same samples have been studied petrographically by optical microscopy on thin sections and analyzed by powder X-ray diffraction in order to monitor structural and mineralogical changes as a function of temperature. The method is demonstrated on samples from four geographically widely different sites and it is applied to a larger set of ceramics of Late (ca. AD 900eAD 1450) and Inca (ca. AD 1480eAD 1532) periods from the Northwestern Argentine region, dating to a limited period of time prior to the fall of the Inca Empire. The method is shown to be a powerful tool in revealing archaeological information about the change in firing technologies in the pre-Hispanic societies in the Andean area through time.

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Section: Validating the Methods Through An Experimental Approachsupporting

confidence: 92%

Pottery firing temperatures: a new method for determining the firing temperature of ceramics and burnt clay

Rasmussen

Fuente

Bond

et al. 2012

Journal of Archaeological Science

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“…6. In this connection, we remind the results of Noller et al [3] that reported a slight magnetization hysteresis at 298 K for the Fe-doped gehlenite, and the growth of the magnetic susceptibility with decrease of temperature up to 4 K. The observed magnetic properties are attributed by them to magnetic domains, consisting of mutually interacting antiparallel spins and magnetic ordering (high value of the maximum magnetization) observed at low temperatures to their increasing mutual interactions. They left open the question of the role of magnetic domains in relation to the cationic tetrahedron structural units.…”

Section: Resultssupporting

confidence: 84%

Magnetic Properties of Synthetic Gehlenite Glass Microspheres

et al. 2017

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In the paper, gehlenite amorphous microspheres were prepared by the flame synthesis of a powder precursor. In the first step, the precursor was prepared from a stoichiometric mixture of CaCO3, Al2O3 and SiO2 by a standard solid-state reaction method. Next, the precursor was sprayed into a CH4-O2 flame with the temperature of around 2200• C and molten droplets of synthetic gehlenite were rapidly cooled by distilled water. Structural and detailed magnetic properties were studied by the optical microscopy, X-ray diffraction and QD SQUID magnetometer. The gehlenite microspheres show a complex magnetic behaviour that is a function of the temperature and the magnetic field, e.g. diamagnetism and paramagnetism at 300 K and 2 K, respectively.

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“…The electron configuration of Bi 2þ is 6s 2 6p 1 with 2 P 1/2 ground state and 2 P 3/2 as the first excited state. This excited state can be further separated by crystal field splitting into two sublevels 2 P 3/2 (1) and 2 P 3/2 (2), in order of increasing energy. In fact, the transition 2 P 3/2 (1) !…”

Section: Resultsmentioning

confidence: 99%

“…Since the 1990s, compounds with melilite structure have been intensively studied due to their interesting electrochemical [1], magnetic [2][3][4], luminescence [5 -7] and structural properties [8][9][10]. The melilites are a large family of materials with the general formula [8] A 2 [4] B [4] C 2 O 7 where A is a large cation such as Ca, Sr, Ba, Na, K, Y, lanthanides, Pb or Bi; B is a small cation such as Al, Be, Co, Cu, Cd, Fe, Ga or Mg; and finally C ¼ Si, B, Al, Cr, Ge or V. The number in square brackets [N ] indicates the coordination number (CN) of the element.…”

Section: Introductionmentioning

confidence: 99%

Crystallization and visible–near-infrared luminescence of Bi-doped gehlenite glass

et al. 2018

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Gehlenite glass microspheres, doped with a different concentration of Bi3+ ions (0.5, 1, 3 mol%), were prepared by a combination of solid-state reaction followed by flame synthesis. The prepared glass microspheres were characterized from the point of view of surface morphology, phase composition, thermal and photoluminescence (PL) properties by optical and scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and PL spectroscopy. The closer inspection of glass microsphere surface by SEM confirmed a smooth surface. This was further verified by XRD. The basic thermal characteristics of prepared glasses, i.e. Tg (glass transition temperature), Tx (onset of crystallization peak temperature), Tf (temperature of the inflection point of the crystallization peak) and Tp (maximum of crystallization peak temperature), were estimated from the DSC records. High-temperature XRD experiments in the temperature interval range 600–1100°C were also performed. The PL emission properties of prepared glasses and their polycrystalline analogues (glass crystallized at 1000°C for 10 h) were studied in the visible and near-infrared (NIR) spectral range. When excited at 300 nm, the glasses, as well as their polycrystalline analogues, exhibit broad emission in the visible spectral range from 350 to 650 nm centred at about 410–450 nm, corresponding to Bi3+ luminescence centres. The emission intensity of polycrystalline samples was found to be at least 30 times higher than the emission of their glass analogues. In addition, a weak emission band was observed around 775 nm under 300 nm excitation. This band was attributed to the presence of a minor amount of Bi2+ species in prepared samples. In the NIR spectral range, the broad band emission was observed in the spectral range of 1200–1600 nm with the maxima at 1350 nm. The chemistry of Bi and its oxidation state equilibrium in glasses and polycrystalline matrices is discussed in detail.

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Magnetic properties of calcium-silicates (diopside and gehlenite) doped with iron (III)

Cited by 15 publications

References 1 publication

Pottery firing temperatures: a new method for determining the firing temperature of ceramics and burnt clay

Pottery firing temperatures: a new method for determining the firing temperature of ceramics and burnt clay

Magnetic Properties of Synthetic Gehlenite Glass Microspheres

Crystallization and visible–near-infrared luminescence of Bi-doped gehlenite glass

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