2006/06/30 by S. P. Bayrakci, T. Keller, K. Habicht +1 · 2 citations
Physics and Astronomy · #cond-mat.str-el
paper · pdf · doi:10.1126/science.1127756
published as Science 312, 1926 (2006) · 12 pages, 4 figures
arxiv created 2006/06/30 · arxiv updated 2009/12/01
We use a neutron spin-echo method with μeV resolution to determine the lifetimes of spin waves in the prototypical antiferromagnet MnF2 over the entire Brillouin zone. A theory based on the interaction of magnons with longitudinal spin fluctuations provides an excellent, parameter-free description of the data, except at the lowest momenta and temperatures. This is surprising, given the prominence of alternative theories based on magnon-magnon interactions in the literature. The results and technique open up a new avenue for the investigation of fundamental concepts in magnetism. The technique also allows measurement of the lifetimes of other elementary excitations (such as lattice vibrations) throughout the Brillouin zone.