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Title: High-pressure behavior of superconducting boron-doped diamond

Authors:
; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
DOE - BASIC ENERGY SCIENCESDOE-NNSAFOREIGN
OSTI Identifier:
1368295
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review B; Journal Volume: 95; Journal Issue: 17
Country of Publication:
United States
Language:
ENGLISH

Citation Formats

Abdel-Hafiez, Mahmoud, Kumar, Dinesh, Thiyagarajan, R., Zhang, Q., Howie, R. T., Sethupathi, K., Volkova, O., Vasiliev, A., Yang, W., Mao, H. K., and Rao, M. S. Ramachandra. High-pressure behavior of superconducting boron-doped diamond. United States: N. p., 2017. Web. doi:10.1103/physrevb.95.174519.
Abdel-Hafiez, Mahmoud, Kumar, Dinesh, Thiyagarajan, R., Zhang, Q., Howie, R. T., Sethupathi, K., Volkova, O., Vasiliev, A., Yang, W., Mao, H. K., & Rao, M. S. Ramachandra. High-pressure behavior of superconducting boron-doped diamond. United States. doi:10.1103/physrevb.95.174519.
Abdel-Hafiez, Mahmoud, Kumar, Dinesh, Thiyagarajan, R., Zhang, Q., Howie, R. T., Sethupathi, K., Volkova, O., Vasiliev, A., Yang, W., Mao, H. K., and Rao, M. S. Ramachandra. 2017. "High-pressure behavior of superconducting boron-doped diamond". United States. doi:10.1103/physrevb.95.174519.
@article{osti_1368295,
title = {High-pressure behavior of superconducting boron-doped diamond},
author = {Abdel-Hafiez, Mahmoud and Kumar, Dinesh and Thiyagarajan, R. and Zhang, Q. and Howie, R. T. and Sethupathi, K. and Volkova, O. and Vasiliev, A. and Yang, W. and Mao, H. K. and Rao, M. S. Ramachandra},
abstractNote = {},
doi = {10.1103/physrevb.95.174519},
journal = {Physical Review B},
number = 17,
volume = 95,
place = {United States},
year = 2017,
month = 5
}
  • Boron-doped diamond thin films have been examined before and after high-current-density electrolysis to investigate the morphological and microstructural stability of this new electrode material. The diamond thin films were used to generate chlorine from a solution of 1.0 M HNO{sub 3} + 2.0 M NaCl at current densities of 0.05 and 0.5 A/cm{sup 2} for times up to 20 h. Comparative studies were made using common graphitic electrodes including highly oriented pyrolytic graphite, glassy carbon, and Grafoil{reg_sign}. The electrodes were characterized using four-point probe resistivity measurements, atomic force microscopy, scanning electron microscopy, Raman spectroscopy, x-ray photoelectron spectroscopy, and cyclic voltammetry.more » In all cases, no severe morphological or microstructural damage (i.e., corrosion) was observed on films exposed to the highest current density. There were surface compositional changes in the forms of oxygenation and non-diamond carbon impurity etching that produced an increase in the reaction overpotential. Specifically, the overpotential was supposed to result from a combination of decreased surface conductivity due to the formation of carbon-oxygen functional groups and loss of kinetically active redox sites due to the oxidative etching of nondiamond carbon impurities.« less
  • To develop further diamond related devices, the concentration and spatial location of dopants should be controlled down to the nanometer scale. Scanning transmission electron microscopy using the high angle annular dark field mode is shown to be sensitive to boron doping in diamond epilayers. An analytical procedure is described, whereby local boron concentrations above 10{sup 20} cm{sup −3} were quantitatively derived down to nanometer resolution from the signal dependence on thickness and boron content. Experimental boron local doping profiles measured on diamond p{sup −}/p{sup ++}/p{sup −} multilayers are compared to macroscopic profiles obtained by secondary ion mass spectrometry, avoiding reportedmore » artefacts.« less
  • Graphite BC[sub 2]N has been compressed with Co metal at a pressure of 5.5 GPa and temperatures of 1400-1600[degrees]C. The principal resulting products were crystals (average dimension 3 [mu]m) with cubiclike facets. The powder X-ray diffraction pattern revealed two kinds of cubic phase, in approximately equal amounts, which were identified as diamond and cBN on the basis of their lattice parameters. Microelemental analyses on individual crystal fragments by K-edge electron energy-loss spectroscopy confirmed this disproportionating crystallization scheme: half of the grains were composed of carbon-only signals of which gave fine-structure characteristic of sp[sup 3] bonding and the other half gavemore » spectra characteristic of sp[sup 3] boron and nitrogen. The crystallization of cBN as well as diamond in the catalytic solvent of pure Co metal is observed here for the first time and is of relevance to the mechanism of the accepted catalytic action of cobalt on the hexagonal/cubic transformation. 26 refs., 4 figs., 2 tabs.« less
  • Dense BC{sub x} phases with high boron concentration are predicted to be metastable, superhard, and conductors or superconductors depending on boron concentration. However, up to this point, diamond-like boron rich carbides BC{sub x} (dl-BC{sub x}) phases have been thought obtainable only through high pressure and high temperature treatment, necessitating small specimen volume. Here, we use electron energy loss spectroscopy combined with transmission electron microscopy, Raman spectroscopy, surface Brillouin scattering, laser ultrasonics (LU) technique, and analysis of elastic properties to demonstrate that low pressure synthesis (chemical vapor deposition) of BC{sub x} phases may also lead to the creation of diamond-like boronmore » rich carbides. The elastic properties of the dl-BC{sub x} phases depend on the carbon sp²versus sp³ content, which decreases with increasing boron concentration, while the boron bonds determine the shape of the Raman spectra of the dl-BC{sub x} after high pressure-high temperature treatment. Using the estimation of the density value based on the sp³ fraction, the shear modulus μ of dl-BC₄, containing 10% carbon atoms with sp³ bonds, and dl-B₃C₂, containing 38% carbon atoms with sp³ bonds, were found to be μ = 19.3 GPa and μ = 170 GPa, respectively. The presented experimental data also imply that boron atoms lead to a creation of sp³ bonds during the deposition processes.« less
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