Transverse anisotropy in the mixed-valent Mn_2~(II)Mn_4~(III)Mn_3~(IV) single-molecule magnet

摘要

High-frequency electron paramagnetic resonance measurements have been performed on a single-crystal sample of a recently discovered mixed valent Mn_2~(II)Mn_4~(III)Mn_3~(IV) single-molecule magnet, with a spin S=17/2 ground state. Frequency, temperature and field-orientation dependent studies confirm previously reported axial magnetic anisotropy parameters and also provide clear evidence for higher order (fourth and sixth) transverse terms that are responsible for the magnetic quantum tunneling observed in this system.