Structural and magnetic phase transitions in Na1-δFeAs
Structural and magnetic phase transitions in Na1-δFeAs
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DOI：
10.1103/physrevb.80.020504
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发表时间：
2009-07-01
影响因子：
3.7
通讯作者：
Dai, Pengcheng
中科院分区：
文献类型：
--
作者：
Li, Shiliang;de la Cruz, Clarina;Dai, Pengcheng
我们利用中子散射研究了 Na1-δ FeAs (T-c=23 K) 单晶和粉末样品的自旋和晶格结构。从室温冷却后，该系统经历了一系列相变：首先在 49 K 时将晶体对称性从四方晶系变为斜方晶系，然后以与 LaFeAsO 相似的自旋结构和小矩 (0.09 +/- 0.04 mu(B)) 进行反铁磁有序化，最后在约 23 K 以下变得超导。这些结果证实，反铁磁有序化对于母体化合物来说是普遍存在的。砷化铁超导体，并表明结构相变温度和磁相变温度的分离是由于系统 c 轴交换耦合的减少。
We use neutron scattering to study the spin and lattice structures of single crystal and powder samples of Na1-delta FeAs (T-c=23 K). Upon cooling from room temperature, the system goes through a series of phase transitions: first changing the crystal symmetry from tetragonal to orthorhombic at 49 K, then ordering antiferromagnetically with a spin structure similar to that of LaFeAsO and a small moment (0.09 +/- 0.04 mu(B)), and finally becoming superconducting below about 23 K. These results confirm that antiferromagnetic order is ubiquitous for the parent compounds of the iron arsenide superconductors and suggest that the separated structural and magnetic phase-transition temperatures are due to the reduction in the c-axis exchange coupling of the system.