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Elementary Excitations in Antiquadrupolar, Antiferrimagnetic and Antiferromagnetic Biquadratic Spin Systems (S = 3/2)
Author(s) -
Błaszczak E.,
Aksamit J.
Publication year - 2002
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(200205)231:1<85::aid-pssb85>3.0.co;2-u
Subject(s) - magnon , antiferromagnetism , spins , condensed matter physics , physics , spin (aerodynamics) , ferrimagnetism , ferromagnetism , spin wave , isotropy , heisenberg model , quasiparticle , phase (matter) , quantum mechanics , magnetization , magnetic field , thermodynamics , superconductivity
The magnon and quadron spectrum is calculated in a two‐sublattice system of localized spins S = 3/2 with the bilinear Heisenberg and isotropic biquadratic interactions. The calculations are performed in the (1/ z ) 0 approximation in the high‐density scheme ( z is the number of spins interacting with any given spin) using diagrammatic methods for the Racah and standard basis operators. In the antiquadrupolar phase two positive and two negative branches of magnons and quadrons are obtained. In the antiferrimagnetic phase there are two positive and one negative magnon branches as well as one positive and one negative quadron branch. In the antiferromagnetic phase there is one positive and one negative branch of magnons and quadrons. The negative spectra, more pronounced here than in the (considered elsewhere) ferrimagnetic and ferromagnetic phases, give rise to the zero‐point corrections at T = 0 in higher‐order approximations.