High Blocking Temperature of Magnetization and Giant Coercivity in the Azafullerene Tb2 @C79 N with a Single-Electron Terbium-Terbium Bond

Georgios Velkos; Denis S Krylov; Kyle Kirkpatrick; Lukas Spree; Vasilii Dubrovin; Bernd Büchner; Stanislav M Avdoshenko; Valeriy Bezmelnitsyn; Sean Davis; Paul Faust; James Duchamp; Harry C Dorn; Alexey A Popov

doi:10.1002/anie.201900943

High Blocking Temperature of Magnetization and Giant Coercivity in the Azafullerene Tb₂ @C₇₉ N with a Single-Electron Terbium-Terbium Bond

Angew Chem Int Ed Engl. 2019 Apr 23;58(18):5891-5896. doi: 10.1002/anie.201900943. Epub 2019 Mar 27.

Authors

Affiliations

¹ Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069, Dresden, Germany.
² Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul, Republic of Korea.
³ Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, 24061, USA.
⁴ Luna nanoWorks, a Division of, Luna Innovation Inc., 521 Bridge St, Danville, Virginia, USA.

Abstract

The azafullerene Tb₂ @C₇₉ N is found to be a single-molecule 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 @C₇₉ N below 15 K proceeds via quantum tunneling of magnetization with the characteristic time τ_QTM =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.

Keywords: endohedral fullerenes; exchange coupling; metal-metal bonds; single-molecule magnets; terbium.

Abstract

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