Static High-pressure Experiments Research Articles

A rapid compression large-volume press with a high pressure jump above 10GPa within milliseconds.

A high pressure jump through a rapid compression within milliseconds (ms) provides an important approach for searching novel matters and investigating their physical and chemical properties. Herein, we report a unique rapid-compression large volume press with a high pressure jump above 10GPa within 20ms by introducing a Walker-type module and hydraulic accumulators. The sample pressure can be rapidly increased from 1-5GPa to 12-16GPa by different modest compression rates varying from 10-2 to 633.5 GPa/s. The rapid pressure jump on the specimen has been successfully verified through the observed rapid phase transition of ZnTe from semiconductor to metal transitions, as evidenced by the variation in its electrical conductivity. The highest pressure jump of 10.2GPa within a rise time of 16.1ms is achieved, which is significantly higher than previous results (5.8GPa within 20ms) using a Bridgman-type anvils in such an apparatus. We found that rapid compression significantly enhances the phase transformation of C70 fullerene from a disordered graphite to an amorphous phase compared to static high-pressure experiments. The high pressure jump technique developed in this study will thus have great applications in materials science, physics, chemistry, and earth science.

Experimental and computational study of the core-level crossing transition in iridium at high pressure

A core-level crossing (CLC) resulting from extreme compression has been calculated to occur in Ir metal at 80 GPa, analogous to a transition previously reported in Os at 392 GPa. We present results from static high-pressure diffraction experiments and theoretical investigations on the compressive behavior of Ir up to 159 GPa, well above the calculated CLC transition pressure. Neither our experimental nor computational results find evidence for a CLC over this pressure range, and instead, our first-principles calculations suggest that the CLC occurs in Ir at the much higher pressure of 400 GPa. Furthermore, computational analysis of the CLC in Ir, combined with previous work on Os, indicates that CLCs at high pressure are not experimentally detectable. Published by the American Physical Society 2024

New frontiers in extreme conditions science at synchrotrons and free electron lasers

Synchrotrons and free electron lasers are unique facilities to probe the atomic structure and electronic properties of matter at extreme thermodynamical conditions. In this context, ‘matter at extreme pressures and temperatures’ was one of the science drivers for the construction of low emittance 4th generation synchrotron sources such as the Extremely Brilliant Source of the European Synchrotron Radiation Facility and hard x-ray free electron lasers, such as the European x-ray free electron laser. These new user facilities combine static high pressure and dynamic shock compression experiments to outstanding high brilliance and submicron beams. This combination not only increases the data-quality but also enlarges tremendously the accessible pressure, temperature and density space. At the same time, the large spectrum of available complementary x-ray diagnostics for static and shock compression studies opens unprecedented insights into the state of matter at extremes. The article aims at highlighting a new horizon of scientific opportunities based on the synergy between extremely brilliant synchrotrons and hard x-ray free electron lasers.

Discovery of coesite from the martian shergottite Northwest Africa 8657

We report occurrences of coesite in a martian meteorite, expanding previously-reported silica polymorphs such as stishovite (El Goresy et al., 2000), seifertite (Sharp et al., 1999; Goresy et al., 2008), and post-stishovite (El Goresy et al., 2000). The coesite was found in the shock-induced melt regions of NWA 8657, usually coexisting with deformed quartz and silica glass. Three morphological types of coesite have been identified: (I) in a silica-maskelynite assemblage, (II) needle grains, and (III) granular grains embedded in maskelynite. Transmission Electron Microscopy (TEM) shows that all types of coesite appear distributed in silica glass and/or nano-phase maskelynite. The stishovite-like morphology of Type II coesite and the presence of deformed quartz suggest coesite to have inverted from stishovite during decompression. The impact-induced peak pressures and temperatures are estimated at ∼ 18–30 GPa and ∼2000 ℃ respectively, based on static high pressure experiments (Langenhorst and Deutsch, 2012; Zhang et al., 1996). The polymorphs aggregates of silica in NWA 8657 indicate that the shock-induced melts in this meteorite cooled slower than those in other stishovite-bearing martian meteorites, but fast enough to preserve coesite.

(Fe,Ni)2P allabogdanite can be an ambient pressure phase in iron meteorites

An orthorhombic modification of (Fe,Ni)2P, allabogdanite, found in iron meteorites was considered to be thermodynamically stable at pressures above 8 GPa and temperatures of 1673 K according to the results of recent static high-pressure and high-temperature experiments. A hexagonal polymorphic modification of (Fe,Ni)2P, barringerite, was considered to be stable at ambient conditions. Experimental investigation through the solid-state synthesis supported by ab initio calculations was carried out to clarify the stability fields of (Fe,Ni)2P polymorphs. Both experimental and theoretical studies show that Fe2P-allabogdanite is a low-temperature phase stable at ambient conditions up to a temperature of at least 773 K and, therefore, is not necessarily associated with high pressures. This is consistent with the textural relationships of allabogdanite in iron meteorites.

Structural phase transitions in aluminium above 320 GPa

With the application of pressure, a material decreases in volume as described in its equation of state, which is governed by energy considerations. At extreme pressures, common materials are thus expected to transform into new dense phases with extremely compact atomic arrangements that may also have unusual physical properties. For aluminium, first principle calculations have consistently predicted a phase transition sequence fcc–hcp–bcc in a pressure range below 0.5TPa [1–7]. The hcp phase was identified at 217GPa in an experiment (Akahama et al., 2006), and the bcc phase has been recently confirmed in a dynamic ramp-compression experiment coupled with time-resolved X-ray diffraction (Polsin et al. 2017). Here we confirm this observation with a synchrotron-based X-ray diffraction experiment carried out within a diamond-anvil cell and report indications of the onset of the transition towards a bcc structure at pressures beyond 320GPa. With this work, we also demonstrate the possibility of routine static high-pressure experiments with conventional bevelled diamond-anvil geometry in the 0.3–0.4TPa regime.

Crystalline polymeric carbon dioxide stable at megabar pressures

Carbon dioxide is a widespread simple molecule in the Universe. In spite of its simplicity it has a very complex phase diagram, forming both amorphous and crystalline extended phases above 40 GPa. The stability range and nature of these phases are still debated, especially in view of their possible role within the deep carbon cycle. Here, we report static synchrotron X-ray diffraction and Raman high-pressure experiments in the megabar range providing evidence for the stability of the polymeric phase V at pressure-temperature conditions relevant to the Earth’s lowermost mantle. The equation of state has been extended to 120 GPa and, contrary to earlier experimental findings, neither dissociation into diamond and ε-oxygen nor ionization was observed. Severe deviatoric stress and lattice deformation along with preferred orientation are removed on progressive annealing, thus suggesting CO2-V as the stable structure also above one megabar.

Research on viscosity of metal at high pressure

A new experimental technique, the flyer-impact method, is proposed in this article to investigate the viscosity coefficient of shocked metals. In this technique, a shock wave with a sinusoidal perturbation on the front is induced by the sinusoidal profile of the impact surface of the sample by use of a two-stage light-gas gun, and the oscillatory damping process of the perturbation amplitude is monitored by electric pins. The damping processes of aluminum at 78 and 101 GPa and iron at 159 and 103 GPa are obtained by this technique, which supplement the existing data by measuring the viscosity coefficient via a dynamic high-pressure method. Applying the formula of Miller and Ahrens to fit the experimental data, the shear viscosity coefficients of aluminum at 78 and 101 GPa are $$1350\,\pm \,500$$ and $$1200\,\pm \,500~\hbox {Pa}\,\hbox {s}$$ , respectively, and those of iron at 159 and 103 GPa are $$1150\,\pm \,1000$$ and $$4800\,\pm \,1000~\hbox {Pa}\,\hbox {s}$$ , respectively. The values measured by the flyer-impact method, approximately $$10^{3}~\hbox {Pa}\, \hbox {s}$$ , are consistent with those measured by Sakharov’s method, while still greatly differing from those measured by static high-pressure methods. In dynamic high-pressure experiments, the shear viscosity is related to dislocation motion in the solid material, while that in static high-pressure experiments is related to the diffusion motion of atoms or molecules in liquids. Therefore, there are different physical meanings of shear viscosity in dynamic and static high-pressure experiments, and there is no comparability among these results.

Phase boundary of hot dense fluid hydrogen

We investigated the phase transformation of hot dense fluid hydrogen using static high-pressure laser-heating experiments in a laser-heated diamond anvil cell. The results show anomalies in the heating efficiency that are likely to be attributed to the phase transition from a diatomic to monoatomic fluid hydrogen (plasma phase transition) in the pressure range between 82 and 106 GPa. This study imposes tighter constraints on the location of the hydrogen plasma phase transition boundary and suggests higher critical point than that predicted by the theoretical calculations.

Stability of iron crystal structures at 0.3–1.5 TPa

Ab initio molecular dynamics simulations carried out for tetragonal and orthorhombic distortions of iron closely follow the results of static-lattice electronic-structure calculations in revealing that the body-centered cubic (bcc) phase of Fe is mechanically unstable at pressures of 0.3–1.5 TPa and temperatures up to 7000 K. Crystal-structural instabilities originate in the static lattice for the bcc configuration, and are consistent with recent results from both static and dynamic high-pressure experiments. Both theory and experiment thus show that the close-packed (hexagonal, hcp and face-centered cubic, fcc) crystal structures of iron are those relevant to the cores of Earth-like planets.

Polymorphism and decomposition of HE single crystals: Insight from static and shock compression experiments

Understanding the reactive behaviour of high explosive (HE) crystals at thermo-mechanical conditions generated by shock-waves is an important step toward understanding shock-wave initiation of these crystals. Despite the significant differences in time scales and loading rates, static high pressure and high temperature (HP-HT) experiments can provide key results regarding structural and chemical processes in HE crystals at pressures and temperatures relevant to shock initiation. Here, we present selected examples for utilizing optical spectroscopy to understand molecular processes in HE crystals at static HP-HT conditions to gain insight into their shock initiation mechanisms. The relevant results obtained from static studies up to 15 GPa and 700 K on polymorphism and decomposition are presented for cyclotrimethylene trinitramine (RDX) and pentaerythritol tetranitrate (PETN). This work demonstrates that the static HP-HT results in conjunction with shock-wave experiments provide an important approach to elucidate processes related to the initiation of shocked HE crystals, including polymorphic transitions, conformational changes, identification of crystal phases at decomposition, and mechanisms governing shock induced decomposition.

Twin sample chamber for simultaneous comparative transport measurements in a diamond anvil cell

In static high pressure experiments, performed within a diamond anvil cell (DAC), several different methods of thermometry may be employed to determine the temperature of the sample. Due to different DAC designs or particular experimental designs or goals, uncertainties in the determination of the temperature of a given sample exist. To overcome the inaccuracy in comparing the temperature dependence of transport properties of different materials at high pressure, we have used a novel design of resistivity measurement in a twin sample chamber built on an insulated gasket in a DAC. In this design, the transport properties of two samples will be measured simultaneously and therefore the two samples will always be in the same relative temperatures. The uncertainties in the temperatures of the two samples will be exactly the same and therefore their relative phase diagram will be compared precisely. The pressures of the chambers can be slightly different and is easily determined by the ruby pieces placed in each chamber. To demonstrate the feasibility of this method we have compared the superconducting properties of two YBa2Cu3O(7-x) (0 ≤ x ≤ 0.65) samples with slightly different superconducting transition temperatures at ambient pressure as a function of pressures up to 11 GPa. The upper limit of the pressure achieved using this design would be lower than single chamber gaskets. The highest achievable pressure, as in a conventional single hole setup, depends upon the thickness of the gasket, the culet size, the size, and symmetry of the sample chamber. For the twin chamber, it also depends upon the separation of the holes from each other as well as from the edge of the culet.

Jadeite formation in shocked ordinary chondrites

Albitic feldspar in shocked ordinary chondrites (Yamato 791384 L6 and Yamato 75100 H6) and albite recovered from static high-pressure and high-temperature synthetic experiments (Kubo et al., 2010) were investigated with a transmission electron microscope (TEM) subsequent to a conventional micro-Raman spectroscopy analysis to clarify albite dissociation reaction under high-pressure and high-temperature condition. When jadeite forms from albite, SiO2 phase as a residual phase of albite dissociation reaction should accompany jadeite from the stoichiometry. However, albitic feldspar in and adjacent to shock-melt veins of the shocked chondrites dissociates into jadeite+residual amorphous (or poorly-crystallized) material having varied chemical compositions between jadeite and SiO2 phase. TEM observations of albitic feldspar in the shocked chondrites and albite recovered from the static high-pressure and high-temperature synthetic experiments show that jadeite crystallization is initiated by grain refinement of albite (or albitic feldspar). Nucleation occurs along grain-boundaries or at triple-junctions of the fine-grained albite crystal assemblage. Jadeite crystal starts to grow from the nucleus through grain-boundary diffusion. Considering pressure condition recorded in the shock-melt veins of the shocked chondrites, stishovite is the most likely as a residual SiO2 phase accompanying jadeite. High-pressure and high-temperature condition induced by a dynamic event is very short. Stishovite would be hardy formed through a dynamic event due to sluggish nucleation rate of stishovite compared with that of jadeite, thus leading to induce heterogeneous and incomplete albite dissociation reaction; albite dissociates into jadeite+residual amorphous material.

Stability and breakdown of Ca13CO3 melt associated with formation of 13C-diamond in static high pressure experiments up to 43 GPa and 3900 K

Melting of calcium carbonate Ca13CO3, stability of the melt and its decomposition were studied in static high pressure experiments at pressures of 11–43GPa and temperatures of 1600–3900K using diamond anvil cell technique with laser heating. We observed formation of 13C-graphite (below 16GPa) and 13C-diamond (between 16 and 43GPa) on decomposition of the Ca13CO3 melt at temperatures above 3400K. At temperatures below 3400K congruent melting of calcium carbonate was confirmed. The experimental results were applied to construction of the phase diagram of CaCO3 up to 43GPa and 3900K focusing at the melting curve of calcium carbonate and the decomposition phase boundary of CaCO3 melt.

Optical cell for in situ vibrational spectroscopic measurements at high pressures and shear

An optical cell is described for performing simultaneous static high-pressure and shear experiments. This cell design is a modification of the previously designed megabar diamond anvil cell used by Mao and Bell that allows for controlled, remote shear. With this diamond anvil cell, it is possible to use a wide range of existing experimental techniques and pressure media. The cell was validated on a sample of calcite at 5 kbar. Raman measurements show the onset of the phase transformation from calcite to aragonite at 10° of rotation.

Carbon polymorphism in shocked meteorites: Evidence for new natural ultrahard phases

A slice of the Haverö meteorite which belongs to the ureilite class known to contain graphite and diamond was cut and then polished as a thin section using a diamond paste. We identified two carbonaceous areas which were standing out by more than 10 µm in relief over the surface of the silicate matrix suggesting that the carbonaceous phases were not easily polishable by a diamond paste and would therefore imply larger polishing hardness. These areas were investigated by reflected light microscopy, high-resolution Field Emission SEM (FESEM), energy-dispersive X-ray (EDX) analysis, Raman spectroscopy, and were subsequently extracted for in situ synchrotron microbeam X-ray fluorescence (XRF), imaging and X-ray diffraction (XRD). We report here the natural occurrences of one new ultrahard rhombohedral carbon polymorph of the R3m space group which structure is very close to diamond but with a partial occupancy of some of the carbon sites. We also report the natural occurrence of the theoretically predicted 21R diamond polytype with lattice parameters very close to what has been modelized. These findings are of great interests for better understanding the world of carbon polymorphs and diamond polytypes giving new natural materials to investigate. These natural samples demonstrate that the carbon system is even more complex than what is currently thought based on ab initio static lattice calculations and high-pressure experiments since this new ultrahard polymorph has never been predicted nor synthesized.

Pressure Dependence of Interatomic Separation and Thermal Expansivity for Alkali Halides and Periclase (MgO)

In this paper, a new isothermal equation of state is developed based on an approximation for the volume dependence of the Anderson{Gruneisen parameter -T along isotherm. The values of interatomic separation r with the change of pressure for nine alkali halides and periclase were investigated with the help of the new isotherm equation of state. The compression data are used to predict the pressure dependence of the coe-cient of volume thermal expansion. The results are compared with the available experimental data and other theoretical results. The isothermal equation of state (EOS) gives us valu- able information about the change in volume under the in∞uence of pressure at a flxed temperature and is thus re- lated to the compression of solids. The theoretical studies of EOS at high pressure are of wide importance because they help us in planning future high pressure experiments and are also important in comparing static high pressure experiments with shock wave experiments. If we have a phenomenological form of EOS, we can predict the high- -pressure properties and compression behavior of solids with a little efiort by determining the parameters from theoretical calculations or experimental data. Various forms of the isothermal EOS (1{5) have been made to predict correctly high-pressure behaviors, irrespective of the material. In this paper, we derive a new phenomenological EOS based on the approximation for the volume dependence of the Anderson{Gruneisen parameter -T along isotherm (6, 7). At the same time, we use it to calculate the values of interatomic separation r with the change of pressure. The compression data obtained in the present work have also been used to calculate the pressure dependence of the volume thermal expansion coe-cient. In order to examine the validity of presented isothermal EOS under study, we make a comparison of the calculated values and available experimental data as well as earlier theoretical investigations in the case of alkali halides and periclase. The method of analysis is given in Sect. 2. The sys- tematic comparison and discussion of the result are given in Sect. 3.

Classical molecular dynamical simulations of high pressure behavior of alpha cristobalite(SiO2)

Static and dynamic high pressure experiments reveal that the behavior ofα-cristobalite(SiO2) depends on the rate and the nature of stress loading. To understand this behavior wehave carried out extensive molecular dynamics simulations. The response to rapid andsimultaneous increase of the pressures and temperatures to the expected Hugoniot valueswas calculated. These simulations along the simulated Hugoniot path revealed that alphacristobalite transforms to a new six coordinated phase beyond 16 GPa, 1410.3 K.We find that between 16 and 18 GPa, even after equilibrating for a very longtime, the disorder in the stishovite-like phase persists. On release of pressure, thisdisordered state is retained, in agreement with the experimental observations.Simulations under slow pressure increase show that the observation of Cmcm issensitive to pressure steps and that stishovite phase arises through the Cmcmphase.

Phase transition ofMnF2driven by shock compression at pressure of up to33GPa

Rutile-type $\mathrm{Mn}{\mathrm{F}}_{2}$ was shock loaded at pressures of $3.6--33.4\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$ by the impact of flyer plates accelerated by a propellant gun. Recovered samples were examined by x-ray powder diffraction analysis and transmission electron microscopy (TEM). A phase transition from the rutile-type structure to the $\ensuremath{\alpha}\text{\ensuremath{-}}\mathrm{Pb}{\mathrm{O}}_{2}$-type structure was found above $3.6\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$. The yield of the $\ensuremath{\alpha}\text{\ensuremath{-}}\mathrm{Pb}{\mathrm{O}}_{2}$ phase in the recovered samples increased for pressures of up to about $10\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$ and decreased at higher pressures. This phenomenon can be explained by a residual temperature effect. A lamellar pattern consisting of two crystalline phases (rutile and $\ensuremath{\alpha}\text{\ensuremath{-}}\mathrm{Pb}{\mathrm{O}}_{2}$-type $\mathrm{Mn}{\mathrm{F}}_{2}$) was observed in the shocked sample by TEM observation. The shock-induced phase transition from the rutile-type structure to the $\ensuremath{\alpha}\text{\ensuremath{-}}\mathrm{Pb}{\mathrm{O}}_{2}$-type structure was inferred to proceed via fluorite-related structures or a $\mathrm{Pb}{\mathrm{Cl}}_{2}$-type structure by comparison with results of previous static high-pressure experiments.

Re–Os fractionation by sulfide melt–silicate melt partitioning: A new spin

Experiments have been done to assess the role of residual sulfide (melt and crystalline monosulfide solid solution, or MSS) in controlling the behavior of rhenium and osmium during basalt petrogenesis. In order to facilitate efficient separation of the sulfide and silicate phases, sulfide melt–silicate melt partitioning experiments were done at 1200 °C, 10 5 Pa and high gravitational acceleration using a furnace mounted in a centrifuge. Additional (static) high pressure experiments (1.5 GPa; 1200, 1250 °C) were performed to measure both sulfide–silicate and MSS–sulfide partitioning. Results from high pressure experiments show that MSS–sulfide melt partitioning does not significantly fractionate Re from Os, so the behavior of these elements during mantle melting will not be sensitive to the identity of the residual sulfide phase. In contrast, most experiments produced minimum values of D sulfide/silicate, Os/ D sulfide/silicate, Re > 1, with some values > 150, which is the requisite minimum to produce the observed Re/Os fractionation in mantle-derived magmas. D sulfide/silicate for Re varies over a wide range, from > 20,000 to ∼ 20, depending on the fO 2 − fS 2 conditions imposed on an experiment, and defines two coherent groupings, based on fS 2, described by the expressions: log D sulfide/silicate = − 6.95(± 0.20) + 2.39(± 0.04) {1/2 log fS 2 − 1/2 log fO 2} (ΔFMQP > 1.5) log D sulfide/silicate = − 7.79(± 0.44) + 2.90(± 0.11) {1/2 log fS 2 − 1/2 log fO 2} (ΔFMQP < 1) in which ΔFMQP is the difference between the log fS 2 of the sample and that of the fayalite–magnetite–quartz–pyrrhotite buffer at the same temperature. Values of D sulfide/silicate for Re which apply to a specific igneous system can be predicted using the results of this study, combined with estimates of the prevailing fO 2 and fS 2. By this approach, D sulfide/silicate determined from the rhenium content of coexisting sulfide globules and silicate glass for MORB (FAMOUS locality) is similar to predicted values, whereas D sulfide/silicate measured for Loihi is somewhat lower than expected. Generally speaking, values of D sulfide/silicate for Re of ∼ 400–800 are expected for melting of oceanic basalt sources, with deviations in bulk partitioning of Re corresponding to the effect of fO 2 on mineral–melt partition coefficients, or by changes in modal sulfide content. Using the experimental partitioning data, along with reasonable estimates of source sulfur content and degree of melting, the Re–Yb systematics for MORB can be reproduced from a depleted mantle composition provided magmas undergo extensive fractional crystallization and/or magma mixing.