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190 results on '"Velisavljevic, Nenad"'

1. Grain growth phenomenon during pressure-induced phase transformations at room temperature

Author

Levitas, Valery I., Pratoori, Raghunandan, Popov, Dmitry, Park, Changyong, and Velisavljevic, Nenad

Subjects
Condensed Matter - Materials Science
Abstract

Significant grain growth is observed during the high-pressure phase transformations (PTs) at room temperature within an hour for various materials. However, no existing theory explains this phenomenon since nanocrystals do not grow at room temperature even over a time span of several years because of slow diffusion. Here, we suggest a multistep mechanism for the grain growth during $\alpha\rightarrow\omega$ PT in Zr. Phase interfaces and grain boundaries (GBs) coincide and move together under the action of a combined thermodynamic driving forces. Several intermediate steps for such motion are suggested and justified kinetically. Nonhydrostatic stresses due to volume reduction in the growing $\omega$ grain promote continuous growth of the existing $\omega$ grain instead of a new nucleation at other GBs. In situ synchrotron Laue diffraction experiments confirm the main predictions of the theory. The suggested mechanism provides a new insight into synergistic interaction between PTs and microstructure evolution., Comment: Main document: 16 pages, 4 figures; Supplementary document: 21 pages, 12 figures

Published
2024

2. Quantitative kinetic rules for plastic strain-induced $\alpha$-$\omega$ phase transformation in Zr under high pressure

Author

Dhar, Achyut, Levitas, Valery I., Pandey, K. K., Park, Changyong, Somayazulu, Maddury, and Velisavljevic, Nenad

Subjects
Condensed Matter - Materials Science
Abstract

Plastic strain-induced phase transformations (PTs) and chemical reactions under high pressure are broadly spread in modern technologies, friction and wear, geophysics, and astrogeology. However, because of very heterogeneous fields of plastic strain $\mathbf{E}^{p}$ and stress $\mathbf{\sigma}$ tensors and volume fraction $c$ of phases in a sample compressed in a diamond anvil cell (DAC) and impossibility of measurements of $\mathbf{\sigma}$ and $\mathbf{E}^{p}$, there are no strict kinetic equations for them. Here, we develop combined experimental-computational approaches to determine all fields in strongly plastically predeformed Zr and kinetic equation for $\alpha$-$\omega$ PT consistent with experimental data for the entire sample. Kinetic equation depends on accumulated plastic strain (instead of time) and pressure and is independent of plastic strain and deviatoric stress tensors, i.e., it can be applied for various above processes. Our results initiate kinetic studies of strain-induced PTs and provide efforts toward more comprehensive understanding of material behavior in extreme conditions., Comment: 28 pages, 11 figures

Published
2024

8. Structural investigation of antisite-disordered FeGa3 under high-pressure.

Author

Rabello, Aryella F., Ribeiro, Cauê K., Martelli, Valentina, Velisavljevic, Nenad, Popov, Dmitry, Xiao, Yuming, Hearne, Giovanni, and Jiménez, J. Larrea

Subjects
STRUCTURAL stability, CRYSTAL structure, X-ray diffraction, SYMMETRY
Abstract

We investigate the crystal structure stability of the cage compound FeGa3 in the presence of Fe antisite disorder (namely as Fe0.258Ga0.742) using room-temperature x-ray diffraction (XRD) as a function of pressure up to 38 GPa. Our results show a crystal structure instability, with the emergence of a second crystallographic phase of different symmetry at a critical pressure in the range of Pc ≈ 16 - 18 GPa, similar to what was previously reported for pristine FeGa3. Our results are a first step in understanding the effect of pressure in the crystal structure of FeGa3 in the presence of disorder. [ABSTRACT FROM AUTHOR]

Published
2024
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10. Yield strength of CeO2 measured from static compression in a radial diamond anvil cell.

Author

Huston, Larissa Q., Couper, Samantha C., Jacobsen, Matthew, Moss, Eric K., Miyagi, Lowell, Smith, Jesse S., Velisavljevic, Nenad, and Sturtevant, Blake T.

Subjects
CERIUM oxides, DIAMOND anvil cell, FREE electron lasers, DEVIATORIC stress (Engineering), X-ray lasers
Abstract

Cerium oxide (ceria, CeO2) is frequently used as a standard in applications such as synchrotron and x-ray free electron lasers for calibrating x-ray wavelengths and offers the potential for understanding the high pressure properties and deformation mechanisms in a wide range of similar face centered cubic (fcc) materials. In this study, the pressure dependence of the strength of ceria was investigated up to 38 GPa using angle dispersive x-ray diffraction in a radial geometry in a diamond anvil cell. In this experiment, the difference in the stress along the axis of compression and perpendicular to the direction of compression can be determined, giving a quantity known as the differential stress. It was found that the differential stress (t), a measure of the lower bound for yield strength, initially increases rapidly from 0.35 ± 0.06 GPa to 2.2 ± 0.4 GPa at pressures of 1.8 and 3.8 GPa, respectively. Above 4 GPa, t increases more slowly to 13.8 ± 2.6 GPa at a pressure of 38 GPa. The changes in the preferred orientation (texture) of CeO2 with pressure were also measured, allowing for the determination of active deformation mechanisms using an elasto-viscoplastic self-consistent model (EVPSC). It was found that as pressure increased, the [001] direction had a slight preferred orientation along the axis of compression. Our EVPSC model of experimental fiber (cylindrically symmetric) textures and lattice strains were most consistent with dominant slip activity along { 111 } ⟨ 1 1 ¯ 0 ⟩. [ABSTRACT FROM AUTHOR]

Published
2022
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13. Strength of tantalum to 276 GPa determined by two x-ray diffraction techniques using diamond anvil cells.

Author

Perreault, Christopher, Huston, Larissa Q., Burrage, Kaleb, Couper, Samantha C., Miyagi, Lowell, Moss, Eric K., Pigott, Jeffrey S., Smith, Jesse S., Velisavljevic, Nenad, Vohra, Yogesh, and Sturtevant, Blake T.

Subjects
DIAMOND anvil cell, X-ray diffraction, TANTALUM, STRENGTH of materials, EXTREME environments, DIGITAL-to-analog converters
Abstract

Tantalum (Ta) is a metal that has useful properties that make it useful in extreme environments. It is, therefore, important to understand how Ta performs in such extreme conditions by accurately measuring its properties. In this work, the yield strength of tantalum has been measured at pressures up to 276 GPa using axial and radial x-ray diffraction (XRD) methods in diamond anvil cells (DACs). We measured strength using XRD in a radial DAC to 50 GPa, in an axial DAC to 60 GPa using diamonds with standard flat culets, and in a final experiment to 276 GPa using toroidal diamond anvils. The radial XRD data were refined using the Material Analysis Using Diffraction Rietveld software package to extract lattice strain and the yield strength. The axial data were refined using the General Structure Analysis System II and a linewidth method was used to calculate the yield strength. The yield strength measured near ambient pressure was found to be 0.5 GPa and increased with a pressure of up to 50 GPa, where the yield strength plateaued at a value of 2.4 GPa. At pressures above 60 GPa, the strength increased again to a maximum value of 9 GPa at the highest pressure of 276 GPa. The data from the three experiments show good agreement between the methods and previously reported experimental data. This agreement illustrates the value of axial diffraction data for material strength determination and allows for measurements at multi-hundreds of GPa using toroidal DACs. [ABSTRACT FROM AUTHOR]

Published
2022
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14. A MHz X-ray diffraction set-up for dynamic compression experiments in the diamond anvil cell

Author

Husband, Rachel J., primary, Strohm, Cornelius, additional, Appel, Karen, additional, Ball, Orianna B., additional, Briggs, Richard, additional, Buchen, Johannes, additional, Cerantola, Valerio, additional, Chariton, Stella, additional, Coleman, Amy L., additional, Cynn, Hyunchae, additional, Dattelbaum, Dana, additional, Dwivedi, Anand, additional, Eggert, Jon H., additional, Ehm, Lars, additional, Evans, William J., additional, Glazyrin, Konstantin, additional, Goncharov, Alexander F., additional, Graafsma, Heinz, additional, Howard, Alex, additional, Huston, Larissa, additional, Hutchinson, Trevor M., additional, Hwang, Huijeong, additional, Jacob, Sony, additional, Kaa, Johannes, additional, Kim, Jaeyong, additional, Kim, Minseob, additional, Koemets, Egor, additional, Konôpková, Zuzana, additional, Langenhorst, Falko, additional, Laurus, Torsten, additional, Li, Xinyang, additional, Mainberger, Jona, additional, Marquardt, Hauke, additional, McBride, Emma E., additional, McGuire, Christopher, additional, McHardy, James D., additional, McMahon, Malcolm I., additional, McWilliams, R. Stewart, additional, Méndez, Alba S. J., additional, Mondal, Anshuman, additional, Morard, Guillaume, additional, O'Bannon, Earl F., additional, Otzen, Christoph, additional, Pépin, Charles M., additional, Prakapenka, Vitali B., additional, Prescher, Clemens, additional, Preston, Thomas R., additional, Redmer, Ronald, additional, Roeper, Michael, additional, Sanchez-Valle, Carmen, additional, Smith, Dean, additional, Smith, Raymond F., additional, Sneed, Daniel, additional, Speziale, Sergio, additional, Spitzbart, Tobias, additional, Stern, Stephan, additional, Sturtevant, Blake T., additional, Sztuk-Dambietz, Jolanta, additional, Talkovski, Peter, additional, Velisavljevic, Nenad, additional, Vennari, Cara, additional, Wu, Zhongyan, additional, Yoo, Choong-Shik, additional, Zastrau, Ulf, additional, Jenei, Zsolt, additional, and Liermann, Hanns-Peter, additional

Published
2023
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19. A MHz X-ray diffraction set-up for dynamic compression experiments in the diamond anvil cell

Author

Husband, Rachel J., Strohm, Cornelius, Appel, Karen, Ball, Orianna B., Briggs, Richard, Buchen, Johannes, Cerantola, Valerio, Chariton, Stella, Coleman, Amy, Cynn, Hyunchae, Dattelbaum, Dana, Dwivedi, Anand, Eggert, Jon H., Ehm, Lars, Evans, William J., Glazyrin, Konstantin, Goncharov, Alexander, Graafsma, Heinz, Howard, Alexander, Huston, Larissa, Hutchinson, Trevor M., Hwang, Huijeong, Jacob, Sony, Kaa, Johannes, Kim, Jaeyong, Kim, Minseob, Koemets, Egor, Konôpková, Zuzana, Langenhorst, Falko, Laurus, Torsten, Li, Xinyang, Mainberger, Jona, Marquardt, Hauke, McBride, Emma E., McGuire, Christopher, McHardy, James, McMahon, Malcolm I., McWilliams, R. Stewart, Méndez, Alba S. J., Mondal, Anshuman, Morard, Guillaume, O'Bannon, Earl, Otzen, Christoph, Pépin, Charles, Prakapenka, Vitali, Prescher, Clemens, Preston, Thomas, Redmer, Ronald, Roeper, Michael, Sanchez-Valle, Carmen, Smith, Dean, Smith, Raymond F., Sneed, Daniel, Speziale, Sergio, Spitzbart, Tobias, Stern, Stephan, Sturtevant, Blake, Sztuk-Dambietz, Jolanta, Talkovski, Peter, Velisavljevic, Nenad, Vennari, Cara, Wu, Zhongyan, Yoo, Choong-Shik, Zastrau, Ulf, Jenei, Zsolt, and Liermann, Hanns-Peter

Subjects
ddc:550
Abstract

Journal of synchrotron radiation 30(4), 671 - 685 (2023). doi:10.1107/S1600577523003910, An experimental platform for dynamic diamond anvil cell (dDAC) research hasbeen developed at the High Energy Density (HED) Instrument at the EuropeanX-ray Free Electron Laser (European XFEL). Advantage was taken of the highrepetition rate of the European XFEL (up to 4.5 MHz) to collect pulse-resolvedMHz X-ray diffraction data from samples as they are dynamically compressed atintermediate strain rates ( 10 3 s1), where up to 352 diffraction images can becollected from a single pulse train. The set-up employs piezo-driven dDACscapable of compressing samples in 340 ms, compatible with the maximumlength of the pulse train (550 ms). Results from rapid compression experimentson a wide range of sample systems with different X-ray scattering powers arepresented. A maximum compression rate of 87 TPa s1 was observed duringthe fast compression of Au, while a strain rate of 1100 s1 was achievedduring the rapid compression of N2 at 23 TPa s1., Published by Wiley-Blackwell, [Erscheinungsort nicht ermittelbar]

Published
2023
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21. CO2 laser heating system for in situ radial x-ray absorption at 16-BM-D at the Advanced Photon Source

Author

Childs, Christian, primary, Smith, Dean, additional, Smith, G. Alexander, additional, Ellison, Paul, additional, Sneed, Daniel, additional, Hinton, Jasmine, additional, Siska, Emily, additional, Pigott, Jeffrey S., additional, Rod, Eric, additional, O’Donnell, William, additional, Salem, Ran, additional, Sturtevant, Blake, additional, Scharff, R. Jason, additional, Velisavljevic, Nenad, additional, Park, Changyong, additional, and Salamat, Ashkan, additional

Published
2022
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22. Structure and properties of pseudomorphically transformed bcc Mg in Mg/Nb multilayered nanolaminates studied using synchrotron X-ray diffraction.

Author

Jain, Manish, Velisavljevic, Nenad, Baldwin, J. Kevin, Knezevic, Marko, Mara, Nathan A., Beyerlein, Irene J., and Pathak, Siddhartha

Subjects
*X-ray diffraction, *BODY centered cubic structure, *SYNCHROTRONS, *X-ray diffraction measurement, *DIAMOND anvil cell, *CRYSTAL structure
Abstract

We utilize synchrotron X-ray diffraction measurements, conducted inside a diamond anvil cell, to analyze the high-pressure stability of Mg/Nb multilayered nanocomposites of equal (1:1) and unequal (1:10) thickness ratios. At larger layer thicknesses, Mg in these nanocomposites exists in its traditional hexagonal close packed (hcp) structure, while below a critical layer thickness of 7–8 nm, the Mg structure is found to transform into an interface strain-induced metastable pseudomorphic body center cubic (bcc) crystal structure. The hcp Mg present in the larger layer thicknesses exhibits an hcp-to-bcc phase transformation at pressures greater than 44 GPa, and this pressure value is found to vary between the equal and unequal Mg/Nb nanocomposite thickness ratios. On the other hand, the pseudomorphic bcc Mg structure is stable up to pressures of 60 GPa. Additionally, the compressibility of the pseudomorphic bcc Mg structure under pressure is shown to be fundamentally different from the bulk (nonlaminated) bcc Mg structure formed under high pressures. These results indicate that interface strain engineering, and an appropriate choice of the adjacent layer material, might be a viable pathway for tuning the structure and properties of the pseudomorphic bcc Mg structure. [ABSTRACT FROM AUTHOR]

Published
2019
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25. Pressure-Induced Enhancement of Thermoelectric Figure of Merit and Structural Phase Transition in TiNiSn

Author

Baker, Jason L, Park, Changyong, Kenney-Benson, Curtis, Sharma, Vineet Kumar, Kanchana, V, Vaitheeswaran, G, Pickard, Chris J, Cornelius, Andrew, Velisavljevic, Nenad, Kumar, Ravhi S, Park, Changyong [0000-0002-3363-5788], Vaitheeswaran, G [0000-0002-2320-7667], Kumar, Ravhi S [0000-0002-1967-1619], and Apollo - University of Cambridge Repository

Subjects
3403 Macromolecular and Materials Chemistry, 34 Chemical Sciences, 51 Physical Sciences
Abstract

Half-Heusler thermoelectric materials are potential candidates for high thermoelectric efficiency. We report high-pressure thermoelectric and structural property measurements, density functional theory calculations on the half-Heusler material TiNiSn, and an increase of 15% in the relative dimensionless figure of merit, ZT, around 3 GPa. Thermal and electrical properties were measured utilizing a specialized sample cell assembly designed for the Paris-Edinburgh large-volume press to a maximum pressure of 3.5 GPa. High-pressure structural measurements performed up to 50 GPa in a diamond-anvil cell indicated the emergence of a new high-pressure phase around 20 GPa. A first-principles structure search performed using an ab initio random structure search approach identified the high-pressure phase as an orthorhombic type, in good agreement with the experimental results.

Published
2021
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26. CO2 laser heating system for in situ radial x-ray absorption at 16-BM-D at the Advanced Photon Source.

Author

Childs, Christian, Smith, Dean, Smith, G. Alexander, Ellison, Paul, Sneed, Daniel, Hinton, Jasmine, Siska, Emily, Pigott, Jeffrey S., Rod, Eric, O'Donnell, William, Salem, Ran, Sturtevant, Blake, Scharff, R. Jason, Velisavljevic, Nenad, Park, Changyong, and Salamat, Ashkan

Subjects
EXTENDED X-ray absorption fine structure, X-ray absorption, HEATING, OPTICAL measurements, ACHROMATISM
Abstract

We present a portable CO2 laser heating system for in situ x-ray absorption spectroscopy (XAS) studies at 16-BM-D (High Pressure Collaborative Access Team, Advanced Photon Source, Argonne National Laboratory). Back scattering optical measurements are made possible by the implementation of a Ge beamsplitter. Optical pyrometry is conducted in the near-infrared, and our temperature measurements are free of chromatic aberration due to the implementation of the peak-scaling method [A. Kavner and W. R. Panero, Phys. Earth Planet. Inter. 143–144, 527–539 (2004) and A. Kavner and C. Nugent, Rev. Sci. Instrum. 79, 024902 (2008)] and mode scrambling of the input signal. Laser power stabilization is established using electronic feedback, providing a steady power over second timescales [Childs et al., Rev. Sci. Instrum. 91, 103003 (2020)]—crucial for longer XAS collections. Examples of in situ high pressure–temperature extended x-ray absorption fine structure measurements of ZrO2 are presented to demonstrate this new capability. [ABSTRACT FROM AUTHOR]

Published
2022
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28. X-ray Free Electron Laser-Induced Synthesis of ε-Iron Nitride at High Pressures

Author

Hwang, Huijeong, primary, Kim, Taehyun, additional, Cynn, Hyunchae, additional, Vogt, Thomas, additional, Husband, Rachel J., additional, Appel, Karen, additional, Baehtz, Carsten, additional, Ball, Orianna B., additional, Baron, Marzena A., additional, Briggs, Richard, additional, Bykov, Maxim, additional, Bykova, Elena, additional, Cerantola, Valerio, additional, Chantel, Julien, additional, Coleman, Amy L., additional, Dattlebaum, Dana, additional, Dresselhaus-Marais, Leora E., additional, Eggert, Jon H., additional, Ehm, Lars, additional, Evans, William J., additional, Fiquet, Guillaume, additional, Frost, Mungo, additional, Glazyrin, Konstantin, additional, Goncharov, Alexander F., additional, Jenei, Zsolt, additional, Kim, Jaeyong, additional, Konôpková, Zuzana, additional, Mainberger, Jona, additional, Makita, Mikako, additional, Marquardt, Hauke, additional, McBride, Emma E., additional, McHardy, James D., additional, Merkel, Sébastien, additional, Morard, Guillaume, additional, O’Bannon, Earl F., additional, Otzen, Christoph, additional, Pace, Edward J., additional, Pelka, Alexander, additional, Pépin, Charles M., additional, Pigott, Jeffrey S., additional, Prakapenka, Vitali B., additional, Prescher, Clemens, additional, Redmer, Ronald, additional, Speziale, Sergio, additional, Spiekermann, Georg, additional, Strohm, Cornelius, additional, Sturtevant, Blake T., additional, Velisavljevic, Nenad, additional, Wilke, Max, additional, Yoo, Choong-Shik, additional, Zastrau, Ulf, additional, Liermann, Hanns-Peter, additional, McMahon, Malcolm I., additional, McWilliams, R. Stewart, additional, and Lee, Yongjae, additional

Published
2021
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37. HPCAT: A Static Compression Science Sector at the Advance Photon Source

Author

PARK, Changyong, primary, BOMMANNAVAR, Arun S., additional, CHOW, Paul, additional, FERRY, Richard A., additional, HRUBIAK, Rostislav, additional, KENNEY-BENSON, Curtis, additional, MENG, Yue, additional, POPOV, Dmitry, additional, ROD, Eric, additional, SHEN, Guoyin, additional, SMITH, Jesse S., additional, SOMAYAZULU, Maddury S., additional, VELISAVLJEVIC, Nenad, additional, and XIAO, Yuming, additional

Published
2019
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38. Anomalous Conductivity in the Rutile Structure Driven by Local Disorder

Author

Smith, Dean, primary, Sneed, Daniel, additional, Dasenbrock-Gammon, Nathan, additional, Snider, Elliot, additional, Smith, G. Alexander, additional, Childs, Christian, additional, Pigott, Jeffrey S., additional, Velisavljevic, Nenad, additional, Park, Changyong, additional, Lawler, Keith V., additional, Dias, Ranga P., additional, and Salamat, Ashkan, additional

Published
2019
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44. The phase diagram of ammonium nitrate.

Author

Chellappa, Raja S., Dattelbaum, Dana M., Velisavljevic, Nenad, and Sheffield, Stephen

Subjects
PHASE diagrams, AMMONIUM nitrate, PRESSURE, TEMPERATURE effect, SYNCHROTRONS, X-ray diffraction, POLYMORPHISM (Crystallography)
Abstract

The pressure-temperature (P-T) phase diagram of ammonium nitrate (AN) [NH4NO3] has been determined using synchrotron x-ray diffraction (XRD) and Raman spectroscopy measurements. Phase boundaries were established by characterizing phase transitions to the high temperature polymorphs during multiple P-T measurements using both XRD and Raman spectroscopy measurements. At room temperature, the ambient pressure orthorhombic (Pmmn) AN-IV phase was stable up to 45 GPa and no phase transitions were observed. AN-IV phase was also observed to be stable in a large P-T phase space. The phase boundaries are steep with a small phase stability regime for high temperature phases. A P-V-T equation of state based on a high temperature Birch-Murnaghan formalism was obtained by simultaneously fitting the P-V isotherms at 298, 325, 446, and 467 K, thermal expansion data at 1 bar, and volumes from P-T ramping experiments. Anomalous thermal expansion behavior of AN was observed at high pressure with a modest negative thermal expansion in the 3-11 GPa range for temperatures up to 467 K. The role of vibrational anharmonicity in this anomalous thermal expansion behavior has been established using high P-T Raman spectroscopy. [ABSTRACT FROM AUTHOR]

Published
2012
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45. Calibration of an isotopically enriched carbon-13 layer pressure sensor to 156 GPa in a diamond anvil cell.

Author

Qiu, Wei, Baker, Paul A., Velisavljevic, Nenad, Vohra, Yogesh K., and Weir, Samuel T.

Subjects
ISOTOPE separation, DIAMOND cutting, MICROWAVE plasmas, CHEMICAL vapor deposition, PRESSURE transducers, EPITAXY, SURFACE enhanced Raman effect
Abstract

An isotopically enriched 13C homoepitaxial diamond layer of 6±1 μm thickness was grown on top of a brilliant cut diamond anvil by a microwave plasma chemical vapor deposition process for application as a pressure sensor. This isotopically enriched diamond tip was then used in conjunction with a natural isotopic abundance diamond anvil to generate high pressure on the sample. We provide a calibration for the 13C Raman mode of this extremely thin epitaxial layer to 156 GPa using ruby fluorescence and the equation of state of copper as secondary pressure standards. The nonlinear calibration of the 13C Raman mode pressure sensor is compared with similar calibrations of 12C Raman edge and a good agreement is obtained. The Raman signal from the 13C epitaxial layer remained a distinct singlet to 156 GPa, and pressure calibration is independent of sample mechanical strength or the diamond anvil geometry. The use of even thinner layer would allow calibration further into ultrahigh pressure regime where the use of other optical sensors has proven to be difficult. [ABSTRACT FROM AUTHOR]

Published
2006
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