Bayrakci S P, Keller T, Habicht K, Keimer B
Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany.
Science. 2006 Jun 30;312(5782):1926-9. doi: 10.1126/science.1127756.
We used a neutron spin-echo method with microelectron-volt 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 spin waves (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.
我们使用具有微电子伏特分辨率的中子自旋回波方法，在整个布里渊区确定典型反铁磁体MnF₂中自旋波的寿命。基于自旋波（磁振子）与纵向自旋涨落相互作用的理论，除了在最低动量和温度下，对数据提供了出色的、无参数描述。鉴于文献中基于磁振子-磁振子相互作用的替代理论的突出地位，这一结果令人惊讶。这些结果和技术为磁性基本概念的研究开辟了一条新途径。该技术还允许在整个布里渊区测量其他基本激发的寿命，例如晶格振动。
