Abstract
Inelastic neutron scattering (INS) experiments under applied magnetic field at low temperatures show detailed low-lying magnetic excitations in the so-called tridiminshed iron icosahedron magnetic molecule. The magnetic molecule consists of nine iron () and three phosphorous atoms that are situated on the 12 vertices of a nearly perfect icosahedron. The three phosphorous atoms form a plane that separates the iron cluster into two weakly coupled three- and six-ion fragments, and , respectively. The magnetic field INS results exhibit an ground state expected from a perfect equilateral triangle of the triad with a powder averaged value . Two sets of triplet excitations whose temperature and magnetic field dependence indicate an ground state with two nondegenerate states are attributed to the fragment. The splitting may result from a finite coupling between the two fragments, single-ion anisotropy, antisymmetric exchange couplings, or from magnetic frustration of its triangular building blocks.
- Received 19 February 2014
DOI:https://doi.org/10.1103/PhysRevB.89.180411
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