Observation of strong magnetoelastic coupling in a first-order phase transition of CrOCl
Observation of strong magnetoelastic coupling in a first-order phase transition of CrOCl
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DOI：
10.1103/physrevb.80.144416
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发表时间：
2009-10-01
影响因子：
3.7
通讯作者：
Kremer, Reinhard K.
中科院分区：
文献类型：
--
作者：
Angelkort, Joachim;Woelfel, Alexander;Kremer, Reinhard K.
CrOCl 向低于 T-N=13.5 K 的反铁磁级状态的相变已被确定为一级相变。这种转变伴随着晶格和结构变形，朝向具有 a 轴独特单斜对称性的双重 2b 核上层结构，如温度依赖性 X 射线衍射实验所证明的那样。磁化率和磁化强度测量表明强磁弹性耦合到具有沿 c 的有序力矩的单轴反铁磁体的转变。在接近 27.2 K 的 T-c 处发现了第二个转变，这可能是纯磁起源的，可能表明不相称的磁超结构的形成。 TiOCl、VOCl 和 CrOCl 的不同行为是填充 3d 轨道不同对称性的结果，这导致这些同构化合物的 MO 双层上存在不同的交换相互作用。
The phase transition of CrOCl toward a state of antiferromagnetic order below T-N=13.5 K has been identified as a first-order phase transition. The transition is accompanied by a lattice and structural distortion toward a twofold, 2b nuclear superstructure with a-axis unique monoclinic symmetry, as evidenced by temperature-dependent x-ray diffraction experiments. Magnetic-susceptibility and magnetization measurements indicate a transition with strong magnetoelastic coupling to a uniaxial antiferromagnet with ordered moments along c. A second transition is discovered at T-c approximate to 27.2 K that is presumably of purely magnetic origin and might indicate the formation of an incommensurate magnetic superstructure. The different behaviors of TiOCl, VOCl, and CrOCl are the result of the different symmetries of the filled 3d orbitals, which lead to different exchange interactions on the MO double layers of these isostructural compounds.