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Limitations of the Giant Spin Hamiltonian in Explaining Magnetization Tunneling in a Single-Molecule Magnet

A. Wilson·J. Lawrence·E-C. Yang·M. Nakano·D. N. Hendrickson·S. Hill
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Abstract

EPR studies of a Ni4 single-molecule magnet yield the zero-field-splitting (zfs) parameters, D, B40 and B44, based on a giant spin approximation (GSA) with S = 4. Experiments on an isostructural Ni-doped Zn4 crystal establish the Ni(II) ion zfs parameters. The 4th-order zfs parameters in the GSA arise from the interplay between the Heisenberg interaction, Js1.s2, and the 2nd-order single-ion anisotropy, giving rise to mixing of higher lying states into the S = 4 state. Consequently, J directly influences the zfs in the ground state, enabling its direct determination by EPR.

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A. Wilson, J. Lawrence, E-C. Yang, M. Nakano, D. N. Hendrickson, S. Hill. 2006-06-09. Limitations of the Giant Spin Hamiltonian in Explaining Magnetization Tunneling in a Single-Molecule Magnet. https://arxiv.org/abs/cond-mat/0606252

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