Exchange coupled pairs of dangling bond spins as a new type of paramagnetic defects in nanodiamonds

V. Yu Osipov; A. I. Shames; A. Ya Vul'

doi:10.1016/j.physb.2009.08.111

Exchange coupled pairs of dangling bond spins as a new type of paramagnetic defects in nanodiamonds

V. Yu Osipov, A. I. Shames, A. Ya Vul'

Department of Physics

Research output: Contribution to journal › Article › peer-review

20 Scopus citations

Abstract

EPR in detonation nanodiamonds (DND) reveals two different signals associated with intrinsic carbon inherited paramagnetic defects. Main carbon inherited EPR signal is narrow intensive Lorentzian-like singlet with g=2.0028 and spin concentration N_s=(6-7)×10¹⁹ spin/g that yields on average 13-15 spins per each DND particle. Additional chemical treatment of DND powder allows practically complete removal of trace amounts of transition metal impurities that reveals a new doublet EPR signal consisting of two relatively narrow lines within the half-field region (g∼4) separated by a distance of 10.4 mT. The intensity of the doublet signal is five orders of magnitude lower than that of the main singlet signal. The former signal has been observed in a wide variety of DND samples disregarding of the impurity level reached and thus may be attributed to some intrinsic defects in DND particles. Such half-field EPR signals correspond to "forbidden" ΔM_s=2 transitions within thermally populated triplet (S=1) levels observed in polycrystalline samples containing exchange dimers-antiferromagnetically coupled spin pairs. Estimates suggest that the concentration of such defects is about one dimer per hundreds DND particles.

Original language	English
Pages (from-to)	4522-4524
Number of pages	3
Journal	Physica B: Condensed Matter
Volume	404
Issue number	23-24
DOIs	https://doi.org/10.1016/j.physb.2009.08.111
State	Published - 15 Dec 2009

Keywords

EPR
Exchange coupled spins
Low temperatures
Nanodiamonds
Paramagnetic defects

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Condensed Matter Physics
Electrical and Electronic Engineering

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10.1016/j.physb.2009.08.111

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title = "Exchange coupled pairs of dangling bond spins as a new type of paramagnetic defects in nanodiamonds",

abstract = "EPR in detonation nanodiamonds (DND) reveals two different signals associated with intrinsic carbon inherited paramagnetic defects. Main carbon inherited EPR signal is narrow intensive Lorentzian-like singlet with g=2.0028 and spin concentration Ns=(6-7)×1019 spin/g that yields on average 13-15 spins per each DND particle. Additional chemical treatment of DND powder allows practically complete removal of trace amounts of transition metal impurities that reveals a new doublet EPR signal consisting of two relatively narrow lines within the half-field region (g∼4) separated by a distance of 10.4 mT. The intensity of the doublet signal is five orders of magnitude lower than that of the main singlet signal. The former signal has been observed in a wide variety of DND samples disregarding of the impurity level reached and thus may be attributed to some intrinsic defects in DND particles. Such half-field EPR signals correspond to {"}forbidden{"} ΔMs=2 transitions within thermally populated triplet (S=1) levels observed in polycrystalline samples containing exchange dimers-antiferromagnetically coupled spin pairs. Estimates suggest that the concentration of such defects is about one dimer per hundreds DND particles.",

keywords = "EPR, Exchange coupled spins, Low temperatures, Nanodiamonds, Paramagnetic defects",

author = "Osipov, {V. Yu} and Shames, {A. I.} and Vul', {A. Ya}",

note = "Funding Information: Authors thank Israeli Ministry of Science, Culture and Sport (MOST Grant # 3-5708) and Russian Foundation for Basic Research (RFBR Grant 09-02-92477-MNKS_a) for the financial support.",

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AU - Osipov, V. Yu

AU - Shames, A. I.

AU - Vul', A. Ya

N1 - Funding Information: Authors thank Israeli Ministry of Science, Culture and Sport (MOST Grant # 3-5708) and Russian Foundation for Basic Research (RFBR Grant 09-02-92477-MNKS_a) for the financial support.

PY - 2009/12/15

Y1 - 2009/12/15

N2 - EPR in detonation nanodiamonds (DND) reveals two different signals associated with intrinsic carbon inherited paramagnetic defects. Main carbon inherited EPR signal is narrow intensive Lorentzian-like singlet with g=2.0028 and spin concentration Ns=(6-7)×1019 spin/g that yields on average 13-15 spins per each DND particle. Additional chemical treatment of DND powder allows practically complete removal of trace amounts of transition metal impurities that reveals a new doublet EPR signal consisting of two relatively narrow lines within the half-field region (g∼4) separated by a distance of 10.4 mT. The intensity of the doublet signal is five orders of magnitude lower than that of the main singlet signal. The former signal has been observed in a wide variety of DND samples disregarding of the impurity level reached and thus may be attributed to some intrinsic defects in DND particles. Such half-field EPR signals correspond to "forbidden" ΔMs=2 transitions within thermally populated triplet (S=1) levels observed in polycrystalline samples containing exchange dimers-antiferromagnetically coupled spin pairs. Estimates suggest that the concentration of such defects is about one dimer per hundreds DND particles.

AB - EPR in detonation nanodiamonds (DND) reveals two different signals associated with intrinsic carbon inherited paramagnetic defects. Main carbon inherited EPR signal is narrow intensive Lorentzian-like singlet with g=2.0028 and spin concentration Ns=(6-7)×1019 spin/g that yields on average 13-15 spins per each DND particle. Additional chemical treatment of DND powder allows practically complete removal of trace amounts of transition metal impurities that reveals a new doublet EPR signal consisting of two relatively narrow lines within the half-field region (g∼4) separated by a distance of 10.4 mT. The intensity of the doublet signal is five orders of magnitude lower than that of the main singlet signal. The former signal has been observed in a wide variety of DND samples disregarding of the impurity level reached and thus may be attributed to some intrinsic defects in DND particles. Such half-field EPR signals correspond to "forbidden" ΔMs=2 transitions within thermally populated triplet (S=1) levels observed in polycrystalline samples containing exchange dimers-antiferromagnetically coupled spin pairs. Estimates suggest that the concentration of such defects is about one dimer per hundreds DND particles.

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Exchange coupled pairs of dangling bond spins as a new type of paramagnetic defects in nanodiamonds

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