FIELD-DEPENDENCE OF THE SOLITON CONTRIBUTION TO THE DYNAMIC CORRELATION-FUNCTION OF A CLASSICAL HEISENBERG-ANTIFERROMAGNET

Recent theoretical and experimental work confirm the existence of soli tons in the nearly classical two-dimensional (2D) Heisenberg antiferro magnet. Previous ac susceptibility measurements on (n-propyl ammonium) (2)MnCl4 or (PAMC), a 2D spin 5/2 antiferromagnet AFM shows that the s usceptibility is strongly dependent on a weak magnetic field (approxim ate to 0.2 Oe) at temperatures below T-C These data provided the motiv ation for a calculation of the field dependence of the static soliton structure factor. This is done by assuming the small field dependent t erm as a perturbation around the static soliton solution. The dynamic part of the correlation function is assumed to result from soliton-mag non scattering in the Born approximation. These field-dependent and dy namic results are combined to obtain the dynamic field-dependent corre lation function. (C) 1997 American Institute of Physics.