Mechanism of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>α</mml:mi><mml:mo>−</mml:mo><mml:mi>ε</mml:mi></mml:mrow></mml:math>phase transformation in iron

Dewaele, Agnès; Denoual, Christophe; Anzellini, Simone; Occelli, F.; Mézouar, M.; Cordier, Patrick; Merkel, Sébastien; Véron, M.; Rausch, Elisabeth

doi:10.1103/physrevb.91.174105

Cited by 60 publications

(53 citation statements)

References 35 publications

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“…Body centered cubic (bcc) to hcp phase transformation of iron occurring around 13 GPa and 300 K is considered to be a prototypical martensitic transition. A number of studies reported that the texture of hcp iron is basically inherited from bcc iron across the transition (Merkel et al, 2004;Miyagi et al, 2008;Ishimatsu et al, 2014;Dewaele et al, 2015;Nishihara et al, 2018). Therefore, we anticipated synthesizing hcp iron samples with different textures in a DAC by using various types of textured bcc iron starting material.…”

Section: High Pressure Apparatus and Iron Starting Materialsmentioning

confidence: 99%

An Experimental Examination of Thermal Conductivity Anisotropy in hcp Iron

et al. 2018

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The Earth's core mainly consists of iron, and its thermal transport properties are of vital importance for our understanding of the thermal evolution and the dynamics of the core and the mantle. However, the reported values of thermal conductivity of iron at the core conditions are so far inconclusive. Although hexagonal closed-packed (hcp) iron is often studied as a proxy metal to investigate the physical properties not only of the inner core, but also the outer core, the anisotropy of the thermal conductivity of hcp iron has never been experimentally examined. Here we report the results of texture analyses by means of synchrotron X-ray diffraction experiments and thermal conductivity measurements on polycrystalline hcp iron up to 44.5 GPa and 300 K. These results indicate that the thermal conductivity of single crystal hcp iron along c axis is about 3-4 times higher than that along a axis, which could have partially caused the controversial values of the thermal conductivity of hcp iron at the Earth's core conditions.

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Section: High Pressure Apparatus and Iron Starting Materialsmentioning

confidence: 99%

An Experimental Examination of Thermal Conductivity Anisotropy in hcp Iron

et al. 2018

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“…In particular, the knowledge of this behavior has many implications for materials science and Earth and planetary sciences. Great efforts have been devoted during the present century to the study of iron [1 -4], titanium [5,6], molybdenum [7 -10], copper [11 -13], magnesium [14,16], tantalum and tungsten [16 -18] among other metals. In contrast, much less attention has been paid to zinc (Zn) and the elements in group 12 of the periodic table.…”

Section: Introductionmentioning

confidence: 99%

High-pressure/high-temperature phase diagram of zinc

Errandonea

MacLeod

Ruiz‐Fuertes

et al. 2018

J. Phys.: Condens. Matter

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The phase diagram of zinc (Zn) has been explored up to 140 GPa and 6000 K, by combining optical observations, x-ray diffraction, and ab initio calculations. In the pressure range covered by this study, Zn is found to retain a hexagonal close-packed (hcp) crystal symmetry up to the melting temperature. The known decrease of the axial ratio (c/a) of the hcp phase of Zn under compression is observed in x-ray diffraction experiments from 300 K up to the melting temperature. The pressure at which c/a reaches [Formula: see text] (≈10 GPa) is slightly affected by temperature. When this axial ratio is reached, we observed that single crystals of Zn, formed at high temperature, break into multiple poly-crystals. In addition, a noticeable change in the pressure dependence of c/a takes place at the same pressure. Both phenomena could be caused by an isomorphic second-order phase transition induced by pressure in Zn. The reported melt curve extends previous results from 24 to 135 GPa. The pressure dependence obtained for the melting temperature is accurately described up to 135 GPa by using a Simon-Glatzel equation: [Formula: see text], where P is the pressure in GPa. The determined melt curve agrees with previous low-pressure studies and with shock-wave experiments, with a melting temperature of 5060(30) K at 135 GPa. Finally, a thermal equation of state is reported, which at room-temperature agrees with the literature.

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“…Given the growth conditions of our solid Ne samples and both the wavelength-and the temperature-dependence of the index of refraction, we take n Ne = 1.10±0.01 [30][31][32]. Therefore, the RC model gives G RC Ne = 1.239 ± 0.024.…”

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confidence: 99%

Measurement of the Hyperfine Quenching Rate of the Clock Transition in Yb171

Singh

Zappala

et al. 2014

Phys. Rev. Lett.

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We report the first experimental determination of the hyperfine quenching rate of the 6s(2) (1)S(0)(F = 1/2) - 6s6p (3)P(0)(F = 1/2) transition in (171)Yb with nuclear spin I = 1/2. This rate determines the natural linewidth and the Rabi frequency of the clock transition of a Yb optical frequency standard. Our technique involves spectrally resolved fluorescence decay measurements of the lowest lying (3)P(0,1) levels of neutral Yb atoms embedded in a solid Ne matrix. The solid Ne provides a simple way to trap a large number of atoms as well as an efficient mechanism for populating (3)P(0). The decay rates in solid Ne are modified by medium effects including the index-of-refraction dependence. We find the (3)P(0) hyperfine quenching rate to be (4.42 ± 0.35) × 10(-2) s(-1) for free (171)Yb, which agrees with recent ab initio calculations.

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Mechanism of theα−εphase transformation in iron

Cited by 60 publications

References 35 publications

An Experimental Examination of Thermal Conductivity Anisotropy in hcp Iron

An Experimental Examination of Thermal Conductivity Anisotropy in hcp Iron

High-pressure/high-temperature phase diagram of zinc

Measurement of the Hyperfine Quenching Rate of the Clock Transition in Yb171

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