Eur. Phys. J. B 32, 287-290 (2003)
https://doi.org/10.1140/epjb/e2003-00099-1

Spin wave propagation in the domain state of a random field magnet

¹ Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA
² NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899
³ Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
⁴ Department of Physics, Brookhaven National Laboratory, Upton, NY 11973
⁵ Department of Physics, University of Toronto, Toronto, Canada M5S IA7

Received: 2 November 2002
Revised: 4 February 2003
Published online: 11 April 2003

Abstract

Inelastic neutron scattering with high wave-vector resolution has characterized the propagation of transverse spin wave modes near the antiferromagnetic zone center in the metastable domain state of a random field Ising magnet. A well-defined, long wavelength excitation is observed despite the absence of long-range magnetic order. Direct comparisons with the spin wave dispersion in the long-range ordered antiferromagnetic state reveal no measurable effects from the domain structure. This result recalls analogous behavior in thermally disordered anisotropic spin chains but contrasts sharply with that of the phonon modes in relaxor ferroelectrics.