An unusual mechanism of building up of high magnetization blocking barrier in an octahedral alkoxide Dy 3+ -based Single-Molecule Magnet

Jérôme Long (1) , Aleksei O Tolpygin (2) , Ekaterina Mamontova (1) , Konstantin A Lyssenko (3) , Munirah D Albaqami (4) , Dan Liu (5) , Liviu F Chibotaru (6) , Yannick Guari (1) , Joulia Larionova (1) , Alexander A Trifonov (2)

1 ICGM - Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier
2 G. A. Razuvaev Institute of Organometallic Chemistry
3 INEOS - A. N. Nesmeyanov Institute of Organoelement Compounds
4 KSU - King Saud University [Riyadh]
5 NPU - Northwestern Polytechnical University [Xi'an]
6 KU Leuven - Catholic University of Leuven = Katholieke Universiteit Leuven

We report a new octahedral [Dy(OCPh3)2(THF)4][BPh4] luminescent SMM exhibiting a massive crystal-field splitting and an anisotropic barrier of 1385 cm 1. Magnetic measurements combined with ab initio analysis reveal a novel mechanism behind the high blocking barrier based on the quench of one-phonon transitions between the three low-lying crystal-field multiplets due to large energy gaps between them exceeding the available phonon energies and forcing the activated relaxation to proceed through the fourth doublet. The observed nonetheless short relaxation time is due to appreciable non-axial anisotropy, which opens a tunnelling relaxation path via interaction with the nuclear spins. Reducing the equatorial crystal field quenches drastically the quantum tunnelling of magnetization, allowing for full exploitation of the high blocking barrier of the complex as in the best known SMMs.

Domaines: Chimie de coordination

Jérôme Long, Aleksei O Tolpygin, Ekaterina Mamontova, Konstantin A Lyssenko, Munirah D Albaqami, et al.. An unusual mechanism of building up of high magnetization blocking barrier in an octahedral alkoxide Dy 3+ -based Single-Molecule Magnet. Inorganic Chemistry Frontiers, 2021, 8 (5), pp.1166-1174. ⟨10.1039/D0QI01267J⟩. ⟨hal-03164904⟩