Open AccessAn insight into what superconducts in polycrystalline boron-doped diamonds based on investigations of microstructure
Author(s) -
Natalia Dubrovinskaia,
Richard Wirth,
J. Wosnitza,
Thomas Papageorgiou,
H. F. Braun,
Nobuyoshi Miyajima,
Leonid Dubrovinsky
Publication year - 2008
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.0801520105
Subject(s) - diamond , boron , microstructure , materials science , superconductivity , material properties of diamond , crystallite , electron energy loss spectroscopy , doping , amorphous solid , transmission electron microscopy , high resolution transmission electron microscopy , chemical vapor deposition , analytical chemistry (journal) , nanotechnology , crystallography , condensed matter physics , metallurgy , chemistry , physics , optoelectronics , organic chemistry , chromatography
The discovery of superconductivity in polycrystalline boron-doped diamond (BDD) synthesized under high pressure and high temperatures [Ekimov,et al. (2004)Nature 428:542–545] has raised a number of questions on the origin of the superconducting state. It was suggested that the heavy boron doping of diamond eventually leads to superconductivity. To justify such statements more detailed information on the microstructure of the composite materials and on the exact boron content in the diamond grains is needed. For that we used high-resolution transmission electron microscopy and electron energy loss spectroscopy. For the studied superconducting BDD samples synthesized at high pressures and high temperatures the diamond grain sizes are ≈1–2 μm with a boron content between 0.2 (2 ) and 0.5 (1 ) at %. The grains are separated by 10- to 20-nm-thick layers and triangular-shaped pockets of predominantly (at least 95 at %) amorphous boron. These results render superconductivity caused by the heavy boron doping in diamond highly unlikely.