TY - JOUR
T1 - Electron spin relaxation of N@C 60 in CS 2
AU - Morton, John J.L.
AU - Tyryshkin, Alexei M.
AU - Ardavan, Arzhang
AU - Porfyrakis, Kyriakos
AU - Lyon, S. A.
AU - Andrew, G.
AU - Briggs, D.
N1 - Funding Information:
We acknowledge helpful discussions with Richard George, and thank Wolfgang Harneit’s group at F.U. Berlin for providing Nitrogen-doped fullerenes, and John Dennis at QMUL, Martin Austwick and Gavin Morley for the purification of N @ C 60 . We thank the Oxford-Princeton Link fund for support. This research is part of the QIP IRC www.qipirc.org (GR/S82176/01). One of the authors (G.A.D.B.) thanks EPSRC for a Professorial Research Fellowship (GR/S15808/01). Another author (A.A.) is supported by the Royal Society. Work at Princeton was supported by the NSF International Office through the Princeton MRSEC Grant No. DMR-0213706 and by the ARO and ARDA under Contract No. DAAD19-02-1-0040.
PY - 2006
Y1 - 2006
N2 - We examine the temperature dependence of the electron spin relaxation times of the molecules N@C 60 and N@C 70 (which comprise atomic nitrogen trapped within a carbon cage) in liquid CS 2 solution. The results are inconsistent with the fluctuating zero-field splitting (ZFS) mechanism, which is commonly invoked to explain electron spin relaxation for S≥1 spins in liquid solution, and is the mechanism postulated in the literature for these systems. Instead, we find an Arrhenius temperature dependence for N@C 60, indicating the spin relaxation is driven primarily by an Orbach process. For the asymmetric N@C 70 molecule, which has a permanent ZFS, we resolve an additional relaxation mechanism caused by the rapid reorientation of its ZFS. We also report the longest coherence time (T 2) ever observed for a molecular electron spin, being 0.25 ms at 170 K.
AB - We examine the temperature dependence of the electron spin relaxation times of the molecules N@C 60 and N@C 70 (which comprise atomic nitrogen trapped within a carbon cage) in liquid CS 2 solution. The results are inconsistent with the fluctuating zero-field splitting (ZFS) mechanism, which is commonly invoked to explain electron spin relaxation for S≥1 spins in liquid solution, and is the mechanism postulated in the literature for these systems. Instead, we find an Arrhenius temperature dependence for N@C 60, indicating the spin relaxation is driven primarily by an Orbach process. For the asymmetric N@C 70 molecule, which has a permanent ZFS, we resolve an additional relaxation mechanism caused by the rapid reorientation of its ZFS. We also report the longest coherence time (T 2) ever observed for a molecular electron spin, being 0.25 ms at 170 K.
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U2 - 10.1063/1.2147262
DO - 10.1063/1.2147262
M3 - Article
C2 - 16409042
AN - SCOPUS:34547649354
SN - 0021-9606
VL - 124
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
IS - 1
M1 - 014508
ER -