Laser heating in the diamond anvil press up to 2000°C sustained and 3000°C pulsed at pressures up to 260 kilobars

Ming, L. C.; Bassett, William A.

doi:10.1063/1.1686822

Cited by 207 publications

(58 citation statements)

References 8 publications

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“…Nd-doped yttrium-aluminum-garnet (YAG) (h = 1.06 txm) lasers, first used by Ming and Bassett [1974], and CO2 lasers (h = 10.6 !•m) [Boehler and Chopelas, 1991] have typical powers of 20 and 150 W, respectively. However, intrinsic power instability of these lasers produced temperature fluctuations of several hundred degrees, a serious problem for accurately measuring phase transitions.…”

Section: Laser Heatingmentioning

confidence: 99%

High‐pressure experiments and the phase diagram of lower mantle and core materials

Boehler

2000

Reviews of Geophysics

382

256

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Abstract. The interpretation of seismic data and computer modeling requires increased accuracy in relevant material properties in order to improve our knowledge of the structure and dynamics of the Earth's deep interior. To obtain such properties, a complementary method to classic shock compression experiments and theoretical calculations is the use of laser-heated diamond cells, which are now producing accurate data on phase diagrams, equations of state, and melting. Data on one of the most important measurements, the melting temperatures of iron at very high pressure, are now converging. Two other issues linking core properties to those of iron are investigated in the diamond cell: One is the melting point depression of iron in the presence of light elements, and the other is the structure of iron at the conditions of the inner core. First measurements on eutectic systems indicate a significant decrease in the melting point depression with increasing pressure, which is in contrast to previous predictions. X-ray diffraction measurements at simultaneously high pressure and high temperature have improved significantly with the installation of high-pressure "beam lines" at synchrotron facilities, and structural measurements on iron are in progress. Considerable efforts have been made to develop new techniques to heat minerals at the conditions of the deep mantle in the diamond cell and to measure their phase relations reliably. Even measurements of the melting behavior of realistic rock compositions at high pressure, previously considered to be impossible in the diamond cell, have been reported. The extrapolated solidus of the lower mantle intersects the geotherm at the core-mantle boundary, which may explain the seismically observed ultra low velocity zone. The diamond cell has great potential for future development and broad application, as new measurements on high-pressure geochemistry at deep mantle and core conditions have opened a new field of research. There are, however, strict experimental requirements for obtaining reliable data, which are summarized in the present paper. Results from recent measurements of melting temperatures and phase diagrams of lower mantle and core materials at very high pressure are reviewed. INTRODUCTIONThe interpretation of seismic data that have gained significantly in resolution and amount in the last few years poses a challenge in the fields of computer modeling, geochemistry, and experimental high-pressure research. A picture has evolved in which the Earth is much more heterogeneous in its internal structure than previously thought [Kellogg et al., 1999], and the causes for these heterogeneities are only poorly understood. The observed lateral and depth variations in seismic velocities may have thermal, structural, dynamical, and/or chemical causes. A key element in the understanding of this complexity is the study of physical and chemical properties of the relevant Earth materials. However, at the very high pressure and temperature conditions of the Earth's deep interior th...

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Section: Laser Heatingmentioning

confidence: 99%

High‐pressure experiments and the phase diagram of lower mantle and core materials

Boehler

2000

Reviews of Geophysics

382

256

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“…3000 K). Since the birth of the LHDAC in the late 1960s [12,13], the LHDAC technique has been widely used in X-ray diffraction, melting point studies, phase equilibrium studies, and chemical analyses of quenched samples [14 -20]. These studies provided data on phase diagram, equation of state, elasticity, composition, and melting curve of planetary materials.…”

Section: Introductionmentioning

confidence: 99%

Nuclear resonant scattering at high pressure and high temperature

Zhao

Sturhahn

Lin

et al. 2004

High Pressure Research

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We introduce the combination of nuclear resonant inelastic X-ray scattering and synchrotron Mössbauer spectroscopy with the laser-heated diamond anvil cell technique for studying magnetic, elastic, thermodynamic, and vibrational properties of materials under high pressures and high temperatures. An Nd:YLF laser, operating in continuous donut mode (TEM 01 ), has been used to heat samples inside a diamond anvil cell from both sides. Temperatures of the laser-heated sample are measured by means of spectral radiometry and by the detailed balance principle of the energy spectra. The temperature measured by the detailed balance principle is in very good agreement with values determined from the thermal radiation spectra fitted to the Planck radiation function up to 1700 K. Nuclear resonant scattering on 57 Fe-containing materials (i.e., Fe, FeO, Fe 2 O 3 ) has been studied up to 2500 K and 100 GPa. A detailed description of the laser-heating optics, temperature determination, the X-ray monochromatization, and the X-ray focusing optics is given in this article.

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“…The starting materials are two synthetic orthopyroxenes with chemical molar compositions of (Mg 0.8 Fe 0.2 )SiO 3 (En80) and (Mg 0.6 Fe 0.4 )SiO 3 (En60), and San Carlos olivine with the composition of (Mg 0.88 Fe 0.12 ) 2 SiO 4 . Experiments were conducted at the 13IDD beamline of the GeoSoilEnviro Consortium for Advanced Radiation Sources and the 16IDB beamline of the High-Pressure Collaborative Access Team at Argonne National Laboratory; both beamlines are optimized for monochromatic x-ray diffraction study of high-P samples with in situ laser heating (11,12). The silicate sample was sandwiched between thin layers of NaCl, which served as thermal insulation during laser heating and as the pressure calibrant (13), placed in a 40-m-diameter sample chamber in a rhenium gasket in a symmetrical diamond anvil cell, raised to specific pressures, heated with yttrium lithium fluoride lasers from both sides, and monitored with x-ray diffraction in situ at high P-T and at ambient T and high P after temperature quench.…”

mentioning

confidence: 99%

Ferromagnesian postperovskite silicates in the D″ layer of the Earth

Mao

Shen

Prakapenka

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

158

109

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Natural olivine with 12 mol % Fe2SiO4 and synthetic orthopyroxenes with 20% and 40% FeSiO3 were studied beyond the pressure-temperature conditions of the core-mantle boundary. All samples were found to convert entirely or partially into the CaIrO3 postperovskite structure, which was recently reported for pure MgSiO3. The incorporation of Fe greatly reduces the pressure needed for the transition and establishes the new phase as the major component of the D؆ layer. With the liquid core as an unlimited reservoir of iron, core-mantle reactions could further enrich the iron content in this phase and explain the intriguing seismic signatures observed in the D؆ layer. The DЉ boundary layer between the crystalline silicate mantle and molten Fe core displays the largest contrast in physical and chemical properties of all of the regions in the Earth and undoubtedly plays a pivotal role in global dynamics and evolution (1-4). Recent high pressure-temperature (P-T) experiments (5, 6) and ab initio theoretical calculations (6-8) indicate that the pure end-member MgSiO 3 transforms to a postperovskite (ppv) phase with the CaIrO 3 structure. The relevance of this new phase to the Earth's interior, however, depends on its stability within the physical-chemical boundary conditions of the DЉ layer. For instance, Murakami et al. (5) observed this transition at 125 GPa and 2,500 K, which is still within the P-T limits of the DЉ layer (Ͻ136 GPa). On the other hand, Shim et al. (9) observed the x-ray diffraction pattern of modified MgSiO 3 perovskite (pv) (9) persisting to higher P (144 Ϯ 10 GPa), and additional peaks consistent with ppv occur only after heating to 2,500 K at 144 GPa, i.e., beyond the limit of the DЉ layer. More importantly, the DЉ layer is in contact with an unlimited source of Fe and possibly FeO in the outer core, and its major phases are dictated by the Fe-rich environment. Does Fe enter the ppv structure? Is the ppv phase stabilized or destabilized by the addition of Fe? Could the Fe content in ppv phase be enriched beyond the mantle ferromagnesian silicate compositions? How does the Fe concentration affect the density buoyancy and thermoelasticity of the ppv phase?Besides shock-wave studies (10), direct experiment on relevant ferromagnesian silicate compositions have never been carried out at the P-T conditions of the DЉ layer. We studied three ferromagnesian silicates in diamond anvil cells to 130-165 GPa with laser heating to 2,500 K and observed the transformation to ppv phase in all three samples. The starting materials are two synthetic orthopyroxenes with chemical molar compositions of (Mg 0.8 Fe 0.2 )SiO 3 (En80) and (Mg 0.6 Fe 0.4 )SiO 3 (En60), and San Carlos olivine with the composition of (Mg 0.88 Fe 0.12 ) 2 SiO 4 . Experiments were conducted at the 13IDD beamline of the GeoSoilEnviro Consortium for Advanced Radiation Sources and the 16IDB beamline of the High-Pressure Collaborative Access Team at Argonne National Laboratory; both beamlines are optimized for monochromatic x-ray diffraction study o...

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Laser heating in the diamond anvil press up to 2000°C sustained and 3000°C pulsed at pressures up to 260 kilobars

Cited by 207 publications

References 8 publications

High‐pressure experiments and the phase diagram of lower mantle and core materials

High‐pressure experiments and the phase diagram of lower mantle and core materials

Nuclear resonant scattering at high pressure and high temperature

Ferromagnesian postperovskite silicates in the D″ layer of the Earth

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