Universität zu Köln

Mueller, Jan, Speziale, Sergio, Efthimiopoulos, Ilias ORCID: 0000-0001-6542-8188, Jahn, Sandro ORCID: 0000-0002-2137-8833 and Koch-Mueller, Monika (2016). Raman spectroscopy of siderite at high pressure: Evidence for a sharp spin transition. Am. Miner., 101 (12). S. 2638 - 2645. CHANTILLY: MINERALOGICAL SOC AMER. ISSN 1945-3027

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Abstract

We have measured high-pressure Raman spectra of both siderite single-crystalline and polycrystalline powder samples in diamond-anvil cell experiments across the pressure-induced high-spin (HS) to low-spin (LS) transition of Fe2+. Between 43.3 and 45.5 GPa, we observed a color change from transparent to green, which is associated to the spin transition. Furthermore, we calibrated the position of the Raman active nu(1) mode with pressure. In a second diamond-anvil cell experiment, we observed the color change from transparent to green in the form of a transition front passing through the single crystal and collected Raman spectra across the transition front. We were able to constrain the stress variation across this transition front to about 0.2 GPa, well below the resolution of our Raman-based pressure/stress calibration. In contrast to the single crystal, the powder sample shows the spin transition over a pressure range of 5 GPa, which we attribute to intergranular stresses. We conclude that within the resolution of our stress/pressure calibration the spin transition of iron in single-crystalline siderite is sharp.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Mueller, Jan UNSPECIFIED UNSPECIFIED UNSPECIFIED Speziale, Sergio UNSPECIFIED UNSPECIFIED UNSPECIFIED Efthimiopoulos, Ilias UNSPECIFIED orcid.org/0000-0001-6542-8188 UNSPECIFIED Jahn, Sandro UNSPECIFIED orcid.org/0000-0002-2137-8833 UNSPECIFIED Koch-Mueller, Monika UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-253450
DOI:	10.2138/am-2016-5708
Journal or Publication Title:	Am. Miner.
Volume:	101
Number:	12
Page Range:	S. 2638 - 2645
Date:	2016
Publisher:	MINERALOGICAL SOC AMER
Place of Publication:	CHANTILLY
ISSN:	1945-3027
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language LOWER-MANTLE; FECO3; IRON; CARBONATES Multiple languages Geochemistry & Geophysics; Mineralogy Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/25345