Institut Néel, CNRS & Université Joseph Fourier, BP 166, 38042 Grenoble Cedex 9, France.
Phys Rev Lett. 2011 Dec 16;107(25):257205. doi: 10.1103/PhysRevLett.107.257205.
We report magnetization and neutron scattering measurements down to 60 mK on a new family of Fe based kagome antiferromagnets, in which a strong local spin anisotropy combined with a low exchange path network connectivity lead to domain walls intersecting the kagome planes through strings of free spins. These produce unfamiliar slow spin dynamics in the ordered phase, evolving from exchange-released spin flips towards a cooperative behavior on decreasing the temperature, probably due to the onset of long-range dipolar interaction. A domain structure of independent magnetic grains is obtained that could be generic to other frustrated magnets.
我们报告了在一组新的 Fe 基 kagome 反铁磁体中进行的磁化和中子散射测量结果，这些反铁磁体具有强烈的局域各向异性和低交换路径网络连通性，导致畴壁穿过 kagome 面的自由自旋串。这些畴壁在有序相中产生了不熟悉的缓慢自旋动力学，从交换释放的自旋翻转演变为随着温度降低的协同行为，这可能是由于长程偶极相互作用的出现。我们得到了一种独立磁颗粒的畴结构，这种结构可能是其他受挫磁体的普遍特征。
