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Ground-State Energy of Biquadratic Spin Systems (S=3/2) in the (1/z) 1 -Approximation |
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E. Błaszczak
a
, J. Aksamit
b
and A. Franek
a
a Department of Medical Biophysics, Medical University of Silesia, Medyków 18, 40-752 Katowice, Poland b Institute of Physics, Silesian University, Uniwersytecka 4, 40-007 Katowice, Poland |
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| Received: November 12, 2002 |
| Corrections to the molecular-field ground-state energies of the Heisenberg model with isotropic biquadratic interactions (spin S=3/2) are calculated in the (1/z) 1 -approximation using the diagrammatic technique based on the Wick reduction theorem (z is the number of spins interacting with any given spin). The present results for the antiferri- and antiferromagnetic phases complete the previously obtained data for the antiquadrupolar, ferri- and ferromagnetic phases. From among the boundaries between different ground states only that between the antiferri- and antiferromagnetic phases is shifted with respect to its molecular-field value. |
| PACS numbers: 75.10.Jm, 75.30.Ds, 75.30.Et, 75.50.Ee |