ISIS Facility, STFC Oxfordshire OX11 0QX, UK.
J Phys Condens Matter. 2014 Jan 29;26(4):046003. doi: 10.1088/0953-8984/26/4/046003. Epub 2014 Jan 6.
We investigate how the order parameter of a continuous phase transition can be protected from view by symmetry in a magnetic crystal. The symmetry in question forbids atomic displacements and formation of magnetic dipoles, rendering the order parameter invisible in standard x-ray and magnetic neutron Bragg diffraction. Analysis of the allowed magnetic space-groups reveals exact properties of the hidden order parameter. We demonstrate that Bragg spots forbidden by the chemical structure can unveil magnetic hidden order. The method is applied to URu2Si2, which has been thoroughly investigated in the past few decades using all manner of experimental techniques. Starting from the established chemical structure of URu2Si2, we have performed a critical analysis of available data for magnetic neutron Bragg diffraction.
我们研究了在磁晶体中，通过对称性如何保护连续相变的序参量不被观察到。所研究的对称性禁止原子位移和形成磁偶极子，使得标准 X 射线和磁中子布拉格衍射中看不到序参量。对允许的磁空间群的分析揭示了隐藏序参量的精确性质。我们证明了被化学结构禁止的布拉格点可以揭示磁隐藏序。该方法已应用于 URu2Si2，过去几十年中，使用各种实验技术对其进行了彻底的研究。从 URu2Si2 的既定化学结构出发，我们对现有的磁中子布拉格衍射可用数据进行了批判性分析。
