High Temperature Diamond Anvil Cell Research Articles

Discovery of terrestrial allabogdanite (Fe,Ni)2P, and the effect of Ni and Mo substitution on the barringerite-allabogdanite high-pressure transition

Abstract Minerals formed at high pressures are sensitive indicators of extreme pressure-temperature conditions that occur in nature. The discovery of the high-pressure polymorph of (Fe,Ni)2P, allabogdanite in the surficial pyrometamorphic rocks of the Hatrurim Formation (the Mottled Zone) surrounding the Dead Sea basin in Israel is the first terrestrial occurrence of a mineral previously only found in iron meteorites. Stepwise annealing experiments demonstrate that allabogdanite is metastable at ambient pressure and that it irreversibly transforms into its low-pressure polymorph, barringerite, upon heating to 850 ± 50 °C. High-pressure, high-temperature diamond-anvil cell (DAC) experiments confirm the results of annealing experiments. The DAC data indicate that Hatrurim allabogdanite is metastable below 7.4 GPa, and the low-to high-pressure phase transition (barringerite → allabogdanite) occurs at 25 ± 3 GPa and 1400 ± 100 °C. The observed transition pressure of Hatrurim allabogdanite is significantly higher than that of pure synthetic Fe2P (8 GPa) due to partial substitution of Fe for Ni (4 wt%) and Mo (2.5 wt%). Because the influence of substituting impurities on the conditions of phase transitions can be unexpectedly strong, our findings confirm that caution should be exercised when extrapolating data from experiments on synthetic compounds to natural systems. Based on the discovery of terrestrial allabogdanite (Fe,Ni)2P coupled with experiments probing the phase transitions in this natural composition, we contend that terrestrial allabogdanite formed via transformation from barringerite and posit potential scenarios of its formation.

Does Heterogeneous Strain Act as a Control on Seismic Anisotropy in Earth’s Lower Mantle?

Plastic deformation and texture development in minerals of the lower mantle can result in seismic anisotropy, and studying deformation of lower mantle materials is therefore important for interpreting lower mantle flow. Most previous deformation experiments documenting texture development at lower mantle pressures have been conducted on single-phase samples and/or at room temperature. However, real rocks deform at high temperature and are poly-phase and deformation is therefore likely different from that of a single phase. Here we report on high temperature diamond anvil cell deformation experiments on a multiphase assemblage of bridgmanite, ferropericlase, and ringwoodite compressed from ~28 to ~39 GPa and resistively heated at a constant temperature of 1000 K. We employ the elasto-viscoplastic self-consistent (EVPSC) method to model both texture and lattice strain of bridgmanite as a function of deformation mechanisms. Simulations indicate deformation of bridgmanite is accommodated by about half of slip activity on (100)[010] with the remainder split between (100)[001] and/or (100) . Texture in bridgmanite is consistent with most seismic observations in the lowermost mantle. Although there is texture development in both bridgmanite and ringwoodite, ferropericlase does not develop coherent texture throughout the course of the experiment. Analysis of lattice strains suggests that the lack of coherent texture development in ferropericlase is due to heterogeneous plastic deformation resulting from microstructural interactions imposed by other phases. Variations in texturing of bridgmanite and ferropericlase could therefore cause laterally varying, complex anisotropy. Our models for binary mantle-like mixtures of bridgmanite and ferropericlase show that changes in strain and texture partitioning can explain the range of observed lower mantle anisotropies.

Development of a high temperature diamond anvil cell for x ray absorption experiments under extreme conditions

X-ray absorption spectroscopy (XAS) is presently a powerful and established tool to investigate solid and liquid matter at high pressure and high temperature (HP-HT). HP-HT XAS experiments rely on high pressure technology whose continuous development has extended the achievable range up to 100 GPa and more. In high pressure devices, high temperature conditions are typically obtained by using internal and external resistive heaters or by laser heating. We have recently developed a novel design for an internally heated diamond anvil cell (DAC) allowing XAS measurements under controlled high temperature conditions (tested up to about 1300 K). The sample in the new device can be rapidly heated or cooled (seconds or less) so the cell is suitable for studying melting/crystallization dynamics when coupled with a time-resolved XAS setup (second and sub-second ranges). Here we describe the internally heated DAC device which has been realized and tested in experiments on pure selenium at the energy dispersive ODE beamline of Synchrotron SOLEIL. We also present results obtained in XAS experiments of elemental Se using a large volume Paris-Edinburgh press, as an example of the relevance of structural studies of matter under extreme conditions.

Multipurpose high-pressure high-temperature diamond-anvil cell with a novel high-precision guiding system and a dual-mode pressurization device

A novel diamond-anvil cell (DAC) design has been constructed and tested for in situ applications at high-pressure (HP) operations and has proved to be suitable even for HP sample environments at non-ambient temperature conditions. The innovative high-precision guiding mechanism, comparable to a dog clutch, consists of perpendicular planar sliding-plane elements and is integrated directly into the base body of the cylindrically shaped DAC. The combination of two force-generating devices, i.e., mechanical screws and an inflatable gas membrane, allows the user to choose independently between, and to apply individually, two different forcing mechanisms for pressure generation. Both mechanisms are basically independent of each other, but can also be operated simultaneously. The modularity of the DAC design allows for an easy exchange of functional core-element groups optimized not only for various analytical in situ methods but also for HP operation with or without high-temperature (HT) application. For HP-HT experiments a liquid cooling circuit inside the specific inner modular groups has been implemented to obtain a controlled and limited heat distribution within the outer DAC body.

An electrical microheater technique for high-pressure and high-temperature diamond anvil cell experiments

Small electrical heating elements have been lithographically fabricated onto the culets of "designer" diamond anvils for the purpose of performing high-pressure and high-temperature experiments on metals. The thin-film geometry of the heating elements makes them very resistant to plastic deformation during high-pressure loading, and their small cross-sectional area enables them to be electrically heated to very high temperatures with relatively modest currents (approximately = 1 A). The technique also offers excellent control and temporal stability of the sample temperature. Test experiments on gold samples have been performed for pressures up to 21 GPa and temperatures of nearly 2000 K.

An induction heating diamond anvil cell for high pressure and temperature micro-Raman spectroscopic measurements

A new external heating configuration is presented for high-temperature diamond anvil cell instruments. The supporting rockers are thermally excited by induction from an externally mounted copper coil passing a 30 kHz alternating current. The inductive heating configuration therefore avoids the use of breakable wires, yet is capable of cell temperatures of 1100 K or higher. The diamond anvil cell has no resistive heaters, but uses a single-turn induction coil for elevating the temperature. The induction coil is placed near the diamonds and directly heats the tungsten carbide rockers that support the diamond. The temperature in the cell is determined from a temperature-power curve calibrated by the ratio between the intensities of the Stokes and anti-Stokes Raman lines of silicon. The high-pressure transformation of quartz to coesite is successfully observed by micro-Raman spectroscopy using this apparatus. The induction heating diamond anvil cell is thus a useful alternative to resistively heated diamond anvil cells.

Phase transitions of (Mg,Fe)O at megabar pressures

An in situ X-ray diffraction study of magnesiowüstite at high pressures and high temperatures was performed using a high temperature diamond anvil cell and synchrotron radiation. A rhombohedral distortion starts in (Mg 0.20,Fe 0.80)O, (Mg 0.10,Fe 0.90)O, (Mg 0.05,Fe 0.95)O and FeO at the same pressure of 16 GPa. The rhombohedral phase was observed even after laser annealing at megabar pressures. At high temperatures above 1500 °C and megabar pressures, a B1 (rock salt) structured phase was observed to be stable in all samples. A B8 (NiAs) structured phase was not found in magnesiowüstite and was only observed in the end member FeO. The diffraction pattern of the B8 phase was consistent with the calculated intensities for the inverse B8 structure. The results indicate that the stable phase of magnesiowüstite would have a B1 structure under lowermost mantle conditions.

High-pressure phase transition and behavior of protons in brucite Mg(OH) 2 : a high-pressure-temperature study using IR synchrotron radiation

Infrared absorption spectra of brucite Mg (OH)2 were measured under high pressure and high temperature from 0.1 MPa 25 °C to 16 GPa 360 °C using infrared synchrotron radiation at BL43IR of Spring-8 and a high-temperature diamond-anvil cell. Brucite originally has an absorption peak at 3700 cm−1, which is due to the OH dipole at ambient pressure. Over 3 GPa, brucite shows a pressure-induced absorption peak at 3650 cm−1. The pressure-induced peak can be assigned to a new OH dipole under pressure. The new peak indicates that brucite has a new proton site under pressure and undergoes a high-pressure phase transition. From observations of the pressure-induced peak under various P–T condition, a stable region of the high-pressure phase was determined. The original peak shifts to lower wavenumber at −0.25 cm−1 GPa−1, while the pressure-induced peak shifts at −5.1 cm−1 GPa−1. These negative dependences of original and pressure-induced peak shifts against pressure result from enhanced hydrogen bond by shortened O–H···O distance, and the two dependences must result from the differences of hydrogen bond types of the original and pressure-induced peaks, most likely from trifurcated and bent types, respectively. Under high pressure and high temperature, the pressure-induced peak disappears, but a broad absorption band between 3300 and 3500 cm−1 was observed. The broad absorption band may suggest free proton, and the possibility of proton conduction in brucite under high pressure and temperature.

高圧地球科学のフロンティア 高温ＤＡＣを用いた高温高圧下での鉱物中のＯＨの赤外分光

A high temperature diamond anvil cell (HTDAC) was installed in an infrared (IR) microscope at BL43IR of the synchrotron radiation (SR) facility SPring8 to investigate the behavior of “water” in minerals. Since IRSR as an IR light source is more brilliant than a conventional IR source, the IRSR is useful for IR measurements under experimentally difficult conditions such as in a DAC study. In this text, IR microspectroscopy of BL43IR at SPring8, the HTDAC for IR study and the behavior of the proton in brucite (Mg(OH)2) under high temperature and high pressure revealed by IR absorption spectra with IRSR and HTDAC are introduced.

Effects of temperature and composition on the bulk modulus of (Mg,Fe)O

Isothermal static compression data for MgO at 300 and 1100 K were obtained by combining synchrotron X-ray diffraction techniques with an externally heated high-temperature diamond-anvil cell that is capable of achieving pressures greater than 125 GPa at temperatures up to 1100 K. The experiments at 300 K were conducted under both hydrostatic and nonhydrostatic conditions. The deviatoric stress in non-hydrostatic environment significantly effects the measured lattice parameters. Fits to the static compression data of MgO at 300 K yield a bulk modulus of 185(7) GPa and 160(2) GPa under nonhydrostatic and hydrostatic conditions, respectively. The deviatoric stress decreases with increasing temperature, and a nearly hydrostatic condition was achieved at temperatures above 900 K when NaCl was used as a pressure-medium. The bulk modulus of MgO was determined to be 135(3) GPa at a temperature of 1100 K, yielding its temperature derivative of 20.030(3) GPa/K. Comparing these results with previous studies in the system MgO-FeO, shows that the bulk modulus of (Mg,Fe)O decreases with increasing FeO content, from 160 GPa for MgO to 146 GPa for FeO.

Activation volume for arsenic diffusion in germanium

We have measured the effect of pressure on As diffusion in Ge. Diffusion anneals on ion-implanted samples were carried out in a high-temperature diamond anvil cell using fluid argon as a clean, hydrostatic pressure medium. At 575 °C over the pressure range 0.1–4 GPa, pressure slightly enhances the diffusivity, characterized by an activation volume of −1.7±1.4 cm3/mole or −0.12±0.10 times the atomic volume. The results call into question the prevailing view that diffusion of groups III, IV, and V elements are mediated entirely by vacancies. If diffusion of As is mediated entirely by vacancies then either the vacancy formation volume must be unexpectedly low or the energy of vacancy migration must be unexpectedly high.

An externally heated high-temperature diamond anvil cell

An externally heated high-temperature diamond anvil cell

Effect Of Pressure On Boron Diffusion In Silicon

AbstractWe are studying the effect of pressure on boron diffusion in silicon in order to better understand the nature of the point defects responsible for diffusion. Si homoepitaxial layers deltadoped with boron were grown using molecular beam epitaxy. Diffusion anneals were performed in a high temperature diamond anvil cell using fluid argon as a pressure medium. Diffusivities were deduced from B concentration-depth profiles measured with using secondary ion mass spectrometry. Preliminary results indicate that pressure enhances B diffusion in Si at 850 °C, characterized by an average activation volume of -0.125±0.02 times the atomic volume, and thus appear consistent with an interstitial-based diffusion mechanism. Results are compared with previous hydrostatic-pressure studies, with results in biaxially strained films, and with atomistic calculations of activation volumes for self diffusion.

High-Pressure Behavior of Iron Sulfide

ABSTRACTA high-temperature diamond-anvil cell has been developed for in situ characterization of material properties at high pressure and temperature. Using this technique, we have studied the phase relations and physical properties of iron sulfide, FeS, up to 30 GPa and 900 K. In situ X-ray diffraction measurements revealed five polymorphs of FeS, which are closely related to a simple NiAs-type hexagonal structure. In addition to confirming the previously observed phase transitions, we observed a new hexagonal phase of FeS with axial ratio (c/a ) close to ideal closepacking value of 1.63 at high pressure and high temperature. The compression behavior of this new high P-T phase was studied up to 25 GPa at 500 K, 600 K, and 800 K. There is an abrupt shortening of the c axis at about 6 GPa, which may result from an electronic transition, possibly a spin-pairing transition. The c-axis shortening across the electronic transition means that the high P-T phase has substantially shorter interlayer Fe-Fe distances, which would lead to metallization of FeS at high pressure. Changes in density and chemical bonding of FeS at high pressure and temperature will affect the solution and melting behavior in systems such as Fe-FeS. These changes also have important implications for understanding sulfur-bearing iron-cores of planetary bodies.

Ion-pairing in aqueous MgSO 4 solutions along an isochore to 500°C and 11 kbar using Raman spectroscopy in conjunction with the diamond-anvil cell

A high-temperature diamond-anvil cell is used in conjunction with a micro-Raman spectrometer in the study of aqueous fluids containing 0.5 m MgSO 4 along an isochore from room conditions to 500°C and 11 kbar. Gaskets lined with platinum are used to contain the chemically-reactive fluid. Ion-pairing of MgSO 4 is shown to increase with increasing pressure along an isochore with a density of ∼1 g cm −3. Mass-action constants for the reaction Mg 2+ + SO 2− 4 ⇆ MgSO 4 range from 3.5 · 10 1 at 20°C, 1 bar to 1.25 · 10 4 at 500°C, 11.4 kbar. The results agree favorably with those obtained through electrical conductance measurements by V.G. Ritzert and E.U. Franck. The relative abundances of the species are shown as a function of temperature and pressure along the isochore.

High temperature-high pressure experiments on H2O-N2

Abstract The investigation of binary systems in a diamond anvil cell (DAC) reported in literature is limited to about 500 K. In order to extent these investigations to more complex systems like water-nitrogen, the accessible temperature range should be increased considerably. Apart from a high temperature DAC, there is a need for a loading system operating at temepratures as high as 700 K. The technical details of such a set-up and the procedure for the preparation and loading of the DAC with a mixture of known composition are described in this paper. Two important and interesting features of the phase diagram of water-nitrogen at high temperature are the fluid-fluid coexistence surface and the critical curve. This area has only been investigated up to 250 MPa. As an example to show the usefulness of the equipment we present for a mixture containing 67 mole percent of water, the fluid-fluid transitions in the range from 0.13 to 1.73 GPa and 650 to 816 K. This isopleth does not go to as high pressures as might be exspected from low pressure literature data.

High temperature diamond anvil cell with the laser heating

Abstract Focusing laser radiation in the center of a diamond anvil cell (DAC) allows investigations up to P≲100 GPa with the pulsed' and sustained heating to 5000 K2,3. The use of laser radiation permits the exclusion of a heater if the sample itself strongly absorbs the radiation. Many materials are transparent for 1.06 μm YAG-laser radiation usually used for the heating. Therefore it is necessary to mix absorbing radiation powders, for example, graphite, platinum23. The use of the powerful C02-laser for the heating considerably extends the scope of the materials under investigation, as the wavelength radiation Λ= 10 μm is in the range of the strong lattice absorption (absorption coefficient∼ 103-104 cm-l) of many oxides, nitrides and so on.