Overview of Molecular Nanomagnets

Molecular (bottom-up) approach -4------- Classical (top-dowu) approach 

Thermally activated quantum tunneling of the magnetization has first been evidenced in both systems [11-15]. Theoretical discussion of this assumes that thermal processes (principally phonons) promote the molecules up to high levels with small quantum numbers m, not far below the top of the energy barrier, and the molecules then tunnel inelastically to the other side. Thus the transition is almost entirely accomplished via thermal tran- 

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