https://doi.org/10.1140/epjb/e2006-00314-7
Nuclear magnetic resonance study of ultrananocrystalline diamonds
1
Department of Physics, Ben-Gurion University of the Negev, Beer Sheva, 84105, Israel
2
Institute for Experimental Physics, Free University Berlin, Arnimallee 14, 14195 Berlin, Germany
3
NanoCarbon Research Institute, Ltd., 5-4-19 Kashiwa-no-ha, Kashiwa, Chiba, 277-0882, Japan
4
Ioffe Physico-Technical Institute, 26 Polytechnicheskaya, St.Petersburg, 194021, Russia
Corresponding author: a pan@bgu.ac.il
Received:
11
May
2006
Revised:
16
June
2006
Published online:
2
August
2006
We report on a nuclear magnetic resonance (NMR) study of ultrananocrystalline diamond (UNCD) materials produced by detonation technique. Analysis of the 13C and 1H NMR spectra, spin-spin and spin-lattice relaxation times in purified UNCD samples is presented. Our measurements show that UNCD particles consist of a diamond core that is partially covered by a sp2-carbon fullerene-like shell. The uncovered part of outer diamond surface comprises a number of hydrocarbon groups that saturate the dangling bonds. Our findings are discussed along with recent calculations of the UNCD structure. Significant increase in the spin-lattice relaxation rate (in comparison with that of natural diamond), as well as stretched exponential character of the magnetization recovery, are attributed to the interaction of nuclear spins with paramagnetic centers which are likely fabrication-driven dangling bonds with unpaired electrons. We show that these centers are located mainly at the interface between the diamond core and shell.
PACS: 61.46.-w – Nanoscale materials / 76.60.-k – Nuclear magnetic resonance and relaxation / 68.65.-k – Low-dimensional, mesoscopic, and nanoscale systems: structure and nonelectronic properties
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2006