Department of Physics, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA.
Phys Rev Lett. 2013 May 24;110(21):217201. doi: 10.1103/PhysRevLett.110.217201. Epub 2013 May 21.
Using resonant magnetic x-ray photon correlation spectroscopy, we show that the domains of a spiral antiferromagnet enter a jammed state at the onset of long-range order. We find that the slow thermal fluctuations of the domain walls exhibit a compressed exponential relaxation with an exponent of 1.5 found in a wide variety of solidlike jammed systems and can be qualitatively explained in terms of stress release in a stressed network. As the temperature decreases, the energy barrier for fluctuations becomes large enough to arrest further domain wall fluctuations, and the domains freeze into a spatial configuration within 10 K of the Néel temperature. The relaxation times can be fitted with the Vogel-Fulcher law as observed in polymers, glasses, and colloids, thereby indicating that the dynamics of domain walls in an ordered antiferromagnet exhibit some of the universal features associated with jamming behavior.
使用共振磁 X 射线光子相关光谱学，我们表明螺旋反铁磁体的畴在长程有序开始时进入了一种被阻塞的状态。我们发现，畴壁的缓慢热涨落表现出一种压缩指数松弛，其指数为 1.5，这在各种类似固体的阻塞系统中都有发现，并可以根据在受压网络中释放的应力来定性解释。随着温度的降低，涨落的能量势垒变得足够大，以阻止进一步的畴壁涨落，畴在离奈尔温度 10 K 的范围内冻结成一个空间构型。松弛时间可以用 Vogel-Fulcher 定律拟合，正如在聚合物、玻璃和胶体中观察到的那样，这表明有序反铁磁体中畴壁的动力学表现出与阻塞行为相关的一些普遍特征。
