High-pressure Diamond Anvil Cell Research Articles

Imaging magnetic transition of magnetite to megabar pressures using quantum sensors in diamond anvil cell

High-pressure diamond anvil cells have been widely used to create novel states of matter. Nevertheless, the lack of universal in-situ magnetic measurement techniques at megabar pressures makes it difficult to understand the underlying physics of materials’ behavior at extreme conditions, such as high-temperature superconductivity of hydrides and the formation or destruction of the local magnetic moments in magnetic systems. Here, we break through the limitations of pressure on quantum sensors by modulating the uniaxial stress along the nitrogen-vacancy axis and develop the in-situ magnetic detection technique at megabar pressures with high sensitivity (~1μT/Hz\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sim 1{{{\\rm{\\mu }}}}{{{\\rm{T}}}}/\\sqrt{{{{\\rm{Hz}}}}}$$\\end{document}) and sub-microscale spatial resolution. By directly imaging the magnetic field and the evolution of magnetic domains, we observe the macroscopic magnetic transition of Fe3O4 in the megabar pressure range from ferrimagnetic (α-Fe3O4) to weak ferromagnetic (β-Fe3O4) and finally to paramagnetic (γ-Fe3O4). The scenarios for magnetic changes in Fe3O4 characterized here shed light on the direct magnetic microstructure observation in bulk materials at high pressure and contribute to understanding magnetism evolution in the presence of numerous complex factors such as spin crossover, altered magnetic interactions and structural phase transitions.

All-optical method to directly measure the pressure–volume–temperature equation of state of fluids in the diamond anvil cell

We have developed a new all-optical method to directly measure the pressure–volume–temperature (PVT) equation of state (EOS) of fluids and transparent solids in the diamond anvil high pressure cell by measuring the volume of the sample chamber. Our method combines confocal microscopy and white light interference with a new analysis method, which exploits the mutual dependence of sample density and refractive index: Experimentally, the refractive index determines the measured sample chamber thickness (and therefore the measured sample volume/density), yet the sample density is by far the dominant factor in determining the variation in the refractive index with pressure. Our analysis method allows us to obtain a set of values for the density and refractive index, which are mutually consistent and agree with the experimental data within error. We have conducted proof-of-concept experiments on a variety of samples (H2O, CH4, C2H6, C3H8, KCl, and NaCl) at ambient temperature and at high temperatures up to just above 500 K. Our proof-of-concept data demonstrate that our method is able to reproduce known fluid and solid EOS within error. Furthermore, we demonstrate that our method allows us to directly and routinely measure the PVT EOS of simple fluids at GPa pressures up to, at least, 514 K (the highest temperature reached in our study). A reasonable estimation of the known sources of error in our volume determinations indicates that the error is currently ±2.7% at high temperature and that it is feasible to reduce it to ca. ±1% in future work.

Magnetometry in a diamond anvil cell using nitrogen vacancy centers in a nanodiamond ensemble.

The emerging field of optical magnetometry utilizing negative-charged nitrogen vacancy (NV-) centers provides a highly sensitive lab bench technique for spatially resolved physical property measurements. Their implementation in high pressure diamond anvil cell (DAC) environments will become common as other techniques are often limited due to the spatial constraints of the sample chamber. Apparatus and techniques are described here permitting for more general use of magnetic field measurements inside a DAC using continuous wave optical detected magnetic resonance in NV- centers in a layer of nanodiamonds. A microstrip antenna delivers a uniform microwave field to the DAC and is compatible with simple metal gaskets, and the sensor layer of deposited nanodiamonds allows for simple determination of the magnetic field magnitude for B in the 1-100G range. The ferromagnetic transition in iron at 18GPa is measured with the apparatus, along with its hysteretic response.

A review: Comprehensive investigation on bandgap engineering under high pressure utilizing microscopic UV–Vis absorption spectroscopy

Bandgap engineering plays a vital role in material development and device optimization due to its significant impact on the photovoltaic and photoelectricity properties of materials. Nevertheless, it is still a great challenge to accurately control the bandgap of semiconductors to achieve the targeted properties of materials. Recently, pressure-induced bandgap regulation has emerged as a novel and effective tool to regulate bandgap, reveal the intrinsic band nature, and construct the in-depth structure–property relationships therein. In this review, the unique techniques of microscopic in situ steady-state UV–Vis absorption spectroscopy and high-pressure diamond anvil cell are introduced. This technique provides a powerful method to monitor the bandgap behaviors at high pressure. Then, the pressure-triggered bandgap responses are outlined based on several typical semiconductors, including metal halide perovskites, inorganic quantum dots, piezochromic molecular compounds, and two-dimensional semiconductor materials. The summarized structural effects on bandgap evolution and the general principles for bandgap engineering under high pressure are expected to provide guidance for further material design under ambient conditions. Microscopic absorption spectroscopy detection under high pressure is proven to be an ideal platform for developing functional materials and high-performance devices.

Deformation and Transformation Textures in the NaMgF3 Neighborite—Post-Perovskite System

The D″ region of the lower mantle, which lies just above the core–mantle boundary, is distinct from the bulk of the lower mantle in that it exhibits complex seismic heterogeneity and seismic anisotropy. Seismic anisotropy in this region is likely to be largely due to the deformation-induced texture (crystallographic preferred orientation) development of the constituent mineral phases. Thus, seismic anisotropy can provide a marker for deformation processes occurring in this dynamic region of the Earth. Post-perovskite-structured (Mg,Fe)SiO3 is believed to be the dominant mineral phase in many regions of the D”. As such, understanding deformation mechanisms and texture development in post-perovskite is important for the interpretation of observed seismic anisotropy. Here, we report on high-pressure diamond anvil cell deformation experiments on NaMgF3 neighborite (perovskite structure) and post-perovskite. During deformation, neighborite develops a 100 texture, as has been previously observed, both in NaMgF3 and MgSiO3 perovskite. Upon transformation to the post-perovskite phase, an initial texture of {130} at high angles to compression is observed, indicating that the {100} planes of perovskite become the ~{130} planes of post-perovskite. Further compression results in the development of a shoulder towards (001) in the inverse pole figure. Plasticity modeling using the elasto-viscoplastic self-consistent code shows this texture evolution to be most consistent with deformation on (001)[100] with some contribution of glide on (100)[010] and (001)<110> in NaMgF3 post-perovskite. The transformation and deformation mechanisms observed in this study in the NaMgF3 system are consistent with the behavior generally observed in other perovskite–post-perovskite systems, including the MgSiO3 system. This shows that NaMgF3 is a good analog for the mantle bridgmanite and MgSiO3 post-perovskite.

Synthesis and characterization of XeAr2 under high pressure.

The binary Xe-Ar system has been studied in a series of high pressure diamond anvil cell experiments up to 60GPa at 300K. In-situ x-ray powder diffraction and Raman spectroscopy indicate the formation of a van der Waals compound, XeAr2, at above 3.5GPa. Powder x-ray diffraction analysis demonstrates that XeAr2 adopts a Laves MgZn2-type structure with space group P63/mmc and cell parameters a = 6.595 Å and c = 10.716 Å at 4GPa. Density functional theory calculations support the structure determination, with agreement between experimental and calculated Raman spectra. Our DFT calculations suggest that XeAr2 would remain stable without a structural transformation or decomposition into elemental Xe and Ar up to at least 80GPa.

Pressure- and Rate-Dependent Mechanoluminescence with Maximized Efficiency and Tunable Wavelength in ZnS: Mn2+, Eu3.

Mechanoluminescence (ML) has received widespread attention because of potential application in stress sensors and imaging. However, pursuing highly efficient ML remains a challenge due to multifactorial limitations such as pressure and loading rate. Here, we systematically investigate pressure- and rate-dependent ML in Mn2+ and Eu3+ co-doped ZnS in a gigapascal pressure range by using a high-pressure dynamic diamond anvil cell and microsecond time-resolved fluorescent methods and demonstrate the giant tunability in both ML efficiency and wavelength. Compressed from ambient pressure to 11 GPa at different compression rates, ZnS: Mn2+, Eu3+ exhibits a volcano shape in ML emission efficiency with an optimum at ∼3.5 GPa and ∼211.1 GPa/s, at least 1000-fold higher than that measured in the MPa range. The pressure-dependent ML is accompanied with a tunable yellow-to-red emission color change. A combination of high-pressure X-ray diffraction and photoluminescence measurements reveals that the pressure- and rate-dependent ML behavior derives from pressure-induced strengthening of the crystal piezoelectric field and enhanced interaction between the host lattice and doped ions with a significant change of the energy level of the Mn ion. Significantly, the highly efficient ML of ZnS: Mn2+, Eu3+ at the GPa level is reproducible under a compression-decompression process and can be manipulated on a micron scale, implying great potential in mechanical-optical energy conversion and application in dynamic pressure imaging, stress sensors, and multicolor displays.

Pressure-Induced Tunable Charge Carrier Dynamics in Mn-Doped CsPbBr3 Perovskite.

All-inorganic perovskite materials (CsPbX3) have attracted increasing attention due to their excellent photoelectric properties and stable physical and chemical properties. The dynamics of charge carriers affect the photoelectric conversion efficiencies of perovskite materials. Regulating carrier dynamics by changing pressure is interesting with respect to revealing the key microphysical processes involved. Here, ultrafast spectroscopy combined with high-pressure diamond anvil cell technology was used to study the generation and transfer of photoinduced carriers of a Mn-doped inorganic perovskite CsPbBr3 material under pressure. Three components were obtained and assigned to thermal carrier relaxation, optical phonon–acoustic phonon scattering and Auger recombination. The time constants of the three components changed under the applied pressures. Our experimental results show that pressure can affect the crystal structure of Mn-doped CsPbBr3 to regulate carrier dynamics. The use of metal doping not only reduces the content of toxic substances but also improves the photoelectric properties of perovskite materials. We hope that our study can provide dynamic experimental support for the exploration of new photoelectric materials.

Squeezing indium arsenide single crystal to ultrafine nanostructured compact bulk.

Reciprocating pressure-induced phase transition (RPPT) has been proposed as a new approach to synthesize nanostructured bulk materials with clean grain boundary interfaces for structures that undergo reversible pressure-induced phase transitions. The modulation effects on grain size under different cycle numbers of RPPT for InAs were investigated and the initial single-crystal bulk, with a dimensional size of about 30 μm, was transformed into a nanostructure with an average grain size of 7 nm by the utilization of the in situ high-pressure diamond anvil cell (DAC) technique. To verify the DAC findings, compact nanostructured bulk InAs with grain sizes ranging from 2-20 nm (average = 8 nm) and large dimensions (3.2 mm × 3.2 mm × 0.5 mm) was successfully synthesized from single-crystal InAs using a large volume press (LVP). The smaller work function (3.86 eV) and larger bandgap energy (2.64 eV) of the compact nanostructured bulk InAs phase compared to those of single-crystal InAs demonstrated that the nanostructure affected the macroscopic properties of InAs. The findings confirm the feasibility of synthesizing nanostructured bulk materials via RPPT.

Diamond anvil cell with boron-doped diamond heater for high-pressure synthesis and in situ transport measurements

Temperature and pressure are essential parameters in the synthesis, evaluation, and application of functional materials. This study proposes the addition of a heating function to a high-pressure diamond anvil cell (DAC) with in situ measurement probes. The proposed DAC allows for simultaneous control of temperature and pressure within the sample space and can be used to synthesize functional materials under extreme conditions. The various components, namely, the heater, thermometer, and measurement probes, were fabricated with a boron-doped diamond epitaxial film and could be repeatedly used. The developed DAC was used to conduct the high-pressure annealing of a La(O,F)BiS2 single crystal and the high-pressure synthesis of EuFBiS2 superconductors. The proposed technique shows promise for further exploration of superconductors to broaden the research field.

Evolution of hydrogen dissolution and superconductivity in Re-based solid solutions under pressure studied by ab initio calculations

The dissolving of hydrogen (H) into rhenium (Re) is non-negligible in high-pressure experiments involving dense hydrogen and hydrogenous materials, in which rhenium is often used as a gasket material in the high-pressure diamond-anvil cell devices. However, the evolution of hydrogen dissolution into Re and the pressure-induced effects of hydrogen coupling on the superconductivity of metal-based hydrides remain poorly understood experimentally, and theoretical investigations are currently lacking. The present work addresses these issues by applying ab initio calculations for systematically investigating the dissolution of H atoms in Re systems, as well as the electronic properties, lattice dynamics, and electron-phonon coupling (EPC) in the corresponding interstitial Re hydrides. A series of $\mathrm{Re}{\mathrm{H}}_{x}$ compounds with increasing $x$ in the range of 0 to 1 in increments of 0.125 are predicted to be stable at increasing pressures ranging from 1 to 50 GPa. It is found that H atoms generally play the role of impurities in the $\mathrm{Re}{\mathrm{H}}_{x}$ compounds except for $\mathrm{Re}{\mathrm{H}}_{0.5}$ and ReH, where H atoms are integrated into the crystal structure. Moreover, the atomic configuration of the Re host lattice is basically preserved with increasing $x$ and increasing pressure. Further analysis of the superconductive mechanism indicates that an increasing H concentration results in a decreased electronic density of states at the Fermi level and increasing phonon frequencies, which lead to a decrease of EPC \ensuremath{\lambda} and superconducting critical temperature. These findings quantitatively clarify the effects of hydrogen doping on superconductivity in metal-based hydrides, and thereby support the exploration of new types of superconductive hydrides.

High-Pressure Sorption of Hydrogen in Urea.

Hydrogen sorption in urea C(NH2)2O has been probed by direct measurements in Sievert’s apparatus at 7.23 and 11.12 MPa as well as by Raman spectroscopy for the sample compressed and heated in a high-pressure gas-loaded diamond-anvil cell up to 14 GPa. Both these methods consistently indicate the occurrence of small nonstoichiometric sorption of hydrogen in urea phase I. The compression of urea in hydrogen affects the Raman shifts of the C–N bending mode δ and the stretching mode υs. The sorption affects the H2 vibron position too. The sorption of 1.3 × 10–2 at 11.12 MPa corresponds to a stochastic distribution of H2 molecules in channel pores of urea. The mechanism leading to this stochastic sorption involves strong correlations between the swollen nanodot regions around the pores accommodating H2 molecules and the squeezed neighboring pores too narrow to act as possible sorption sites. This study on the hydrogen-bonded framework (HOF) of urea marks the smallest pores capable of absorbing hydrogen documented so far. This observation also reveals a new class of compounds, which is located between those that absorb large stoichiometric amounts of certain guest molecules and those that do not absorb them at all, namely, the group of compounds that absorb the guests in a stochastic manner.

Applying the cBΩ thermodynamical model to LiF using its equation of state obtained from high pressure diamond anvil cell measurements

High pressure experiments using diamond anvil cells with a quasi-hydrostatic pressure transmitting medium (helium or neon) and coupled with X-ray diffraction have very recently been reviewed and provided equations of state parameters with a unified pressure metrology for all data. Focusing on such an equation of state for LiF, which is a unique crystal possessing the largest reported band gap of any material, here we show that a thermodynamical model, termed cBΩ model, satisfactorily describes the way that the point defect parameters, for various defect processes, are interrelated with bulk properties of the matrix material.

Thermomechanical response of thickly tamped targets and diamond anvil cells under pulsed hard x-ray irradiation

In the laboratory study of extreme conditions of temperature and density, the exposure of matter to high intensity radiation sources has been of central importance. Here, we interrogate the performance of multi-layered targets in experiments involving high intensity, hard x-ray irradiation, motivated by the advent of extremely high brightness hard x-ray sources, such as free electron lasers and 4th-generation synchrotron facilities. Intense hard x-ray beams can deliver significant energy in targets having thick x-ray transparent layers (tampers) around samples of interest for the study of novel states of matter and materials’ dynamics. Heated-state lifetimes in such targets can approach the microsecond level, regardless of radiation pulse duration, enabling the exploration of conditions of local thermal and thermodynamic equilibrium at extreme temperature in solid density matter. The thermal and mechanical responses of such thick layered targets following x-ray heating, including hydrodynamic relaxation and heat flow on picosecond to millisecond timescales, are modeled using radiation hydrocode simulation, finite element analysis, and thermodynamic calculations. Assessing the potential for target survival over one or more exposures and resistance to damage arising from heating and resulting mechanical stresses, this study doubles as an investigation into the performance of diamond anvil high pressure cells under high x-ray fluences. Long used in conjunction with synchrotron x-ray radiation and high power optical lasers, the strong confinement afforded by such cells suggests novel applications at emerging high intensity x-ray facilities and new routes to studying thermodynamic equilibrium states of warm, very dense matter.

Laser cutting apparatus for high energy density and diamond anvil cell science

We present a low-cost, high-resolution laser cutting system designed for use in the fabrication of samples for high energy density physics. Such samples are necessarily small but require precision and repeatability, particularly with the recently available high repetition rates possible at modern facilities. The system allows simultaneous laser cutting, using nanosecond near-infrared laser pulses, and optical microscopy so that the cut can be monitored in real time. The capabilities of the system are demonstrated on a range of materials for both laser-matter interaction targets and components for high pressure diamond anvil cell experiment.

Effects of Microstructure and Sample's Surface to Volume Ratio on Pressure-Induced Nucleation and Transformation to Crystalline and Apparently Amorphous Solids.

Heterogeneous nucleation in a polycrystalline solid occurs (i) at the surface of its container, (ii) at its microstructural sites, namely, grain boundaries, grain junctions, and intergrain-strain regions, and (iii) at the defect sites, namely, dislocations, vacancies, and stacking faults (planar defects) in its single crystal grains. We analyze their thermodynamic and kinetic effects in terms of classical nucleation theory by taking into account (a) the increase in Gibbs free energy, G, due to the lattice misfit of the nuclei forming in the parent phase and (b) the decrease in G due to the angle subtended by the nucleus on the external surface, grain boundaries, and grain junctions. Hence we deduce that several combinations of nucleation sites in different materials and also in different polycrystalline samples of the same material may produce the same energy barrier against nucleation and overall growth. The overall nucleation and growth rates are dependent upon the surface to volume ratio, χ, of a sample in a vessel and the vessel's material. Pressurizing a crystalline solid is known to produce either its polymorphic crystal form or a solid that shows no Bragg peaks and appears amorphous. We argue that when self-diffusion rate becomes slower than the pressurizing rate, (dP/dt)T, a multiplicity of states nucleating at different sites become kinetically frozen on their path to crystal growth. In such a case, the transformed solid would appear amorphous. A solid of high χ would transform to a polymorph when (dP/dt)T is low and to a state that appears amorphous when (dP/dt)T is high. Known studies of 0.08-0.1 cm3 volume samples in diamond-anvil high pressure cells provide qualitative evidence of formation of both crystal polymorphs and apparently amorphous solids. Methods are suggested for observing such an occurrence in large polycrystalline samples.

A New High-Pressure Phase Transition in Natural Gedrite

High-pressure diamond-anvil cell synchrotron X-ray diffraction experiments were conducted on single-crystal samples of natural orthoamphibole; gedrite; with composition; (K0.002Na0.394)(Mg2)(Mg1.637Fe2.245Mn0.004Ca0.022Cr0.003Na0.037Al1.052)(Si6.517Al1.483)O22(OH)2. The samples were compressed at 298 K up to a maximum pressure of 27(1) GPa. In this pressure regime, we observed a displacive phase transition between 15.1(7) and 21(1) GPa from the orthorhombic Pnma phase to a new structure with space group P21/m; which is different from the familiar P21/m structure of cummingtonite and retains the (+, +, −, −) I-beam stacking sequence of the orthorhombic structure. The unit cell parameters for the new phase at 21(1) GPa are a = 17.514(3), b = 17.077(1), c = 4.9907(2) Å and β = 92.882(6)°. The high-pressure P21/m phase is the first amphibole structure to show the existence of four crystallographically distinct silicate double chains. The orthorhombic to monoclinic phase transition is characterized by an increase in the degree of kinking of the double silicate chains and is analogous to displacive phase changes recently reported in orthopyroxenes, highlighting the parallel structural relations and phase transformation behavior of orthorhombic single- and double-chain silicates.

Polymorphism of Mg-monohydrate sulfate kieserite under pressure and its occurrence on giant icy jovian satellites

The high-pressure behaviour of hydrated magnesium sulfate kieserite, MgSO4⋅H2O, has been investigated on isothermal compression at T = 295 K up to 8.3 GPa hydrostatic pressure. The crystal properties of synthetic endmember single crystals were investigated using a high-pressure diamond anvil cell by means of in-situ X-ray diffraction and vibrational spectroscopy methods. The experimental study reveals a second-order phase transition from the monoclinic (C2/c) α-phase to a triclinic (P1¯) β-form at a transition pressure of 2.72 GPa. Elastic properties as determined from precise lattice parameters yield static elasticities as described by third-order Birch-Murnaghan equations of state with V0 = 355.5(4) ų, K0 = 48.1(5) GPa, K’ = 8.1(6) for the low-pressure polymorph (α-MgSO4⋅H2O), and V0 = 355.8(1.8) ų, K0 = 49.3(5.5) GPa, K’ = 4.8(1.0) for the high-pressure polymorph (β-MgSO4⋅H2O). The nature of the phase transition and its reversibility on pressure release make it seem unlikely that the β-polymorph can be recovered at surface conditions on any icy satellite, although in the context of impact events it is proposed to exist, but only on a limited time scale before re-transforming to α-MgSO4⋅H2O. With respect to the icy mantles of Ganymede and Callisto, the depth profile of Ganymede following the established thermal gradients suggest a stability field only for α-MgSO4⋅H2O being relevant to the presumable conditions in the icy mantle. In contrast, the depth profile for Callisto, as corresponding to maximum pressures of approximately 5 GPa, crosses the α-to-β-transition boundary and make the high-pressure polymorph a promising candidate rock-forming mineral for the deep icy mantle of the outermost Galilean moon. In particular the material parameters reported for the α and β form of MgSO4⋅H2O are fundamental to compute the icy mantle dynamics and accurately determine the radial density structure in models of Ganymede and Callisto.

Fly scan apparatus for high pressure research using diamond anvil cells.

The hardware and software used to execute fly scans at Sector 16 of the Advanced Photon Source are described. The system design and capabilities address dimensions and time scales relevant to samples in high pressure diamond anvil cells. The time required for routine sample positioning and centering is significantly reduced, and more importantly, the time savings associated with fly scanning make it feasible for users to routinely generate two-dimensional x-ray transmission and x-ray diffraction maps. Consequently, this facilitates an important shift in high pressure research as experimentalists embrace the study of heterogeneous and minute sample volumes in the diamond anvil cell.

A High-Pressure Diamond-Anvil Cell for Optical Studies at Low Temperatures

A compact high-pressure diamond-anvil cell equipped with an interchangeable force-generating device has been constructed and tested. Force can be applied to the anvils both mechanically using screws or a hydraulic press and pneumatically, by feeding compressed gas into a metal double diaphragm. The cell dimensions (a diameter of 44 mm and a height of 40 mm) allow placing it in a cryostat with an inner diameter of 48 mm, so that the optical axis of the diamond anvils is perpendicular to the cryostat axis. The parts of the diamond cell and the force-generating device are made of non-magnetic materials, which allows investigation in magnetic fields.