6 research outputs found
Inelastic neutron scattering study and Hubbard model description of the antiferromagnetic tetrahedral molecule Ni4Mo12
The tetrameric Ni(II) spin cluster Ni4Mo12 has been studied by INS. The data
were analyzed extensively in terms of a very general spin Hamiltonian, which
includes antiferromagnetic Heisenberg interactions, biquadratic 2-spin and
3-spin interactions, a single-ion magnetic anisotropy, and Dzyaloshinsky-Moriya
interactions. Some of the experimentally observed features in the INS spectra
could be reproduced, however, one feature at 1.65 meV resisted all efforts.
This supports the conclusion that the spin Hamiltonian approach is not adequate
to describe the magnetism in Ni4Mo12. The isotropic terms in the spin
Hamiltonian can be obtained in a strong-coupling expansion of the Hubbard model
at half-filling. Therefore detailed theoretical studies of the Hubbard model
were undertaken, using analytical as well as numerical techniques. We carefully
analyzed its abilities and restrictions in applications to molecular spin
clusters. As a main result it was found that the Hubbard model is also unable
to appropriately explain the magnetism in Ni4Mo12. Extensions of the model are
also discussed.Comment: 12 pages, 12 figure
Exchange interactions and magnetic anisotropy in the ``Ni<span class='mathrm'><sub>4</sub></span>'' magnetic molecule
Postnikov A, Brüger M, Schnack J. Exchange interactions and magnetic anisotropy in the ``Ni<sub>4</sub>'' magnetic molecule. Phase Transitions. 2005;78(1-3):47-59
Observation of field-dependent magnetic parameters in the magnetic molecule Observation of field-dependent magnetic parameters in the magnetic molecule {Ni4Mo12}
Schnack J, Brüger M, Luban M, et al. Observation of field-dependent magnetic parameters in the magnetic molecule Observation of field-dependent magnetic parameters in the magnetic molecule {Ni4Mo12}. Phys. Rev. B. 2006;73(9): 94401