Open AccessSingle Molecule Magnetism with Strong Magnetic Anisotropy and Enhanced Dy∙∙∙Dy Coupling in Three Isomers of Dy‐Oxide Clusterfullerene Dy 2 O@C 82
Author(s) -
Yang Wei,
Velkos Georgios,
Liu Fupin,
Sudarkova Svetlana M.,
Wang Yaofeng,
Zhuang Jiaxin,
Zhang Hanning,
Li Xiang,
Zhang Xingxing,
Büchner Bernd,
Avdoshenko Stanislav M.,
Popov Alexey A.,
Chen Ning
Publication year - 2019
Publication title -
advanced science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.388
H-Index - 100
ISSN - 2198-3844
DOI - 10.1002/advs.201901352
Subject(s) - dysprosium , magnetization , magnetism , metallofullerene , crystallography , magnetic anisotropy , materials science , diamagnetism , relaxation (psychology) , paramagnetism , oxide , endohedral fullerene , anisotropy energy , condensed matter physics , chemistry , molecule , metal , inorganic chemistry , magnetic field , physics , social psychology , psychology , organic chemistry , quantum mechanics , metallurgy
Abstract A new class of single‐molecule magnets (SMMs) based on Dy‐oxide clusterfullerenes is synthesized. Three isomers of Dy 2 O@C 82 with C s (6), C 3v (8), and C 2v (9) cage symmetries are characterized by single‐crystal X‐ray diffraction, which shows that the endohedral Dy−(µ 2 ‐O)−Dy cluster has bent shape with very short Dy−O bonds. Dy 2 O@C 82 isomers show SMM behavior with broad magnetic hysteresis, but the temperature and magnetization relaxation depend strongly on the fullerene cage. The short Dy−O distances and the large negative charge of the oxide ion in Dy 2 O@C 82 result in the very strong magnetic anisotropy of Dy ions. Their magnetic moments are aligned along the Dy−O bonds and are antiferromagnetically (AFM) coupled. At low temperatures, relaxation of magnetization in Dy 2 O@C 82 proceeds via the ferromagnetically (FM)‐coupled excited state, giving Arrhenius behavior with the effective barriers equal to the AFM‐FM energy difference. The AFM‐FM energy differences of 5.4–12.9 cm −1 in Dy 2 O@C 82 are considerably larger than in SMMs with {Dy 2 O 2 } bridges, and the Dy∙∙∙Dy exchange coupling in Dy 2 O@C 82 is the strongest among all dinuclear Dy SMMs with diamagnetic bridges. Dy‐oxide clusterfullerenes provide a playground for the further tuning of molecular magnetism via variation of the size and shape of the fullerene cage.