THE INFLUENCE OF BIQUADRATIC COUPLING AND UNIAXIAL ANISOTROPY ON THE SURFACE MODES IN A SIMPLE CUBIC ANTIFERROMAGNET

摘要

We study the surface spin excitations in a simple cubic two-sublattice Heisenberg antiferromagnet with both biquadratic coupling (a) and uniaxial anisotropy (D, D-S). The combined effect is a lowering or narrowing of the energies, and changes of the range of the system parameters for which these modes can exist. For certain values of the system parameters, the surface antiferromagnetic resonance (SAFMR) mode at the Brillouin zone center can be well resolved from the bulk AFMR mode. (C) 1997 Elsevier Science B.V. [References: 22]