High Blocking Temperature of Magnetization and Giant Coercivity in the Azafullerene Tb2@C79N with a Single-Electron Terbium–Terbium Bond
FEBRUARY 2019
Georgios Velkos, Denis S. Krylov, Kyle Kirkpatrick, Lukas Spree, Vasilii Dubrovin, Bernd Bgchner, Stanislav M. Avdoshenko, Valeriy Bezmelnitsyn, Sean Davis, Paul Faust, James Duchamp, Harry C. Dorn, and Alexey A. Popov
Angewandte Chemie - International Edition, 58, 18, 5391-5896 (2019)
Description
The azafullerene Tb2@C79N is found to be a singlemolecule magnet with a high 100-s blocking temperature of magnetization of 24 K and large coercivity. Tb magnetic moments with an easy-axis single-ion magnetic anisotropy are strongly coupled by the unpaired spin of the single-electron Tb@Tb bond. Relaxation of magnetization in Tb2@C79N below 15 K proceeds via quantum tunneling of magnetization with the characteristic time tQTM = 16 462 : 1230 s. At higher temperature, relaxation follows the Orbach mechanism with a barrier of 757 : 4 K, corresponding to the excited states, in which one of the Tb spins is flipped.