Frustration signatures in the anisotropic model of a nine-spin <Emphasis Type="Italic">s</Emphasis> = 3/2 ring with bond defect |
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Authors: | P Kozłowski M Antkowiak G Kamieniarz |
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Institution: | (1) Department of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland |
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Abstract: | Effects of magnetic frustration in the model of nine-membered antiferromagnetic s = 3/2 molecular spin ring are investigated. We use a Heisenberg spin model with nearest-neighbor interactions, single-ion
anisotropy and with tunable bond defect leading to continuously varying topology: from closed to open ring. In order to identify
a frustrated phase we calculate the full energy spectrum of the model and a number of thermodynamic quantities at low temperature.
The calculations are performed by means of numerically exact methods: quantum transfer matrix and exact diagonalization. It
is shown that total and local magnetizations, nearest-neighbor spin correlations and spin fluctuations can serve as consistent
frustration signatures. Magnetizations and spin-spin correlations are reduced in the frustrated phase whereas fluctuations
and correlations of fluctuations increase. The ground state in a frustrated phase is a m = 1/2 doublet and in the non-frustrated phase a m = 3/2 doublet. In the system studied bipartiteness is not opposite to frustration as there are regions in the parameter space
for which the system is neither bipartite nor frustrated. |
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