Cell assemblies for reproducible multi-anvil experiments (the COMPRES assemblies)

Leinenweber, Kurt; Tyburczy, J. A.; Sharp, T. G.; Soignard, Emmanuel; Diedrich, T.; Petuskey, William B.; Wang, Yanbin; Mosenfelder, J. L.

doi:10.2138/am.2012.3844

Cited by 111 publications

(90 citation statements)

References 39 publications

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“…The cell assembly mainly consists of a boron-epoxy gasket, MgO sleeve pressure medium, graphite heater and ZrO 2 thermal insulation cap. The ZrO 2 cap provides a good thermal insulator that reduces temperature variation in samples 58 . Temperatures were estimated by power-temperature relation curves that were determined in a separate experiment using an identical cell configuration 38 .…”

Section: Methodsmentioning

confidence: 99%

Ultralow viscosity of carbonate melts at high pressures

et al. 2014

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Knowledge of the occurrence and mobility of carbonate-rich melts in the Earth's mantle is important for understanding the deep carbon cycle and related geochemical and geophysical processes. However, our understanding of the mobility of carbonate-rich melts remains poor. Here we report viscosities of carbonate melts up to 6.2 GPa using a newly developed technique of ultrafast synchrotron X-ray imaging. These carbonate melts display ultralow viscosities, much lower than previously thought, in the range of 0.006-0.010 Pa s, which are B2 to 3 orders of magnitude lower than those of basaltic melts in the upper mantle. As a result, the mobility of carbonate melts (defined as the ratio of melt-solid density contrast to melt viscosity) is B2 to 3 orders of magnitude higher than that of basaltic melts. Such high mobility has significant influence on several magmatic processes, such as fast melt migration and effective melt extraction beneath mid-ocean ridges.

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Section: Methodsmentioning

confidence: 99%

Ultralow viscosity of carbonate melts at high pressures

et al. 2014

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“…The sample was compressed using a split-cylinder Kawai-type apparatus with 25.4 mm second-stage tungsten carbide (WC) anvils (T-25) in a 1000 ton press. Prior to compression, the sample was pressed to a 2 mm diameter and 1.5 mm tall pellet and mounted inside a Bayreuth-style 14/8 cell assembly 25 . The sample was heated by a graphite heater and the temperature was monitored using an internal C-type W-Re thermocouple.…”

Section: Large Volume Press Experimentsmentioning

confidence: 99%

Phase stability of theSrMnO3hexagonal perovskite system at high pressure and temperature

et al. 2014

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SrMnO 3 is a perovskite compound which, unlike most perovskites, can be synthesized in three different but closely related polymorphs. In this paper, the first experimental equation of state of the 6H polymorphs is reported. The experimentally determined bulk modulus of SrMnO 3 increases from 115.6(11) GPa in the 4H polymorph to 143.7(17) GPa in the 6H polymorph, while DFT calculations predict a further increase to 172.5(4) GPa in the 3C polymorph. The first in situ observations of transformations between the three known polymorphs, under high pressure and high temperature conditions are also reported. The results are compared with extensive DFT calculations and literature, and it is demonstrated that the 6H polymorph is the thermodynamically stable phase between 5.9(3) and 18.1(2) GPa at zero kelvin. The effect of possible oxygen sub-stoichiometry is also explored, used DFT. Finally, the findings are combined with the existing knowledge of the phase behavior in this system to outline where further knowledge needs to be collected before a PT phase diagram can be constructed for this system. I. INTRODUCTIONInorganic compounds with the formula ABX 3 very often crystallize in the well-known perovskite structure, or distorted derivatives thereof. In the ideal cubic structure, the unit cell can be described by an AX 3 cubic close-packed layer, with B ions in the octahedral holes that are surrounded only by X anions. The packing sequence is abc, a being the first hexagonal layer, b the second layer that covers half the holes in a, and c the third placed on top of b to cover the other half. This class of materials covers a wide range of technologically relevant compounds that can display piezoelectric 1 , ferroelectric 2 , (anti)ferromagnetic 3 , catalytic 4 , semiconducting 5 , metallic 6 or insulating 6 behavior. Due to the widespread use of materials with this structure, it is worthwhile trying to gain a deeper insight into the factors governing phase stability in this type of system.

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“…The device and cell assemblies used are discussed in detail in Refs. [15,16]. A type C thermocouple was used to measure the temperature in each experiment-if the thermocouple broke the experiment was terminated and the result not used.…”

Section: Methodsmentioning

confidence: 99%