Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, 01187, Dresden, Germany.
Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou, 310058, China.
Sci Rep. 2017 Aug 4;7(1):7338. doi: 10.1038/s41598-017-07595-w.
We investigated the anisotropic magnetic properties of CePdAs by magnetic, thermal and electrical transport studies. X-ray diffraction confirmed the tetragonal ThCrSi-type structure and the high-quality of the single crystals. Magnetisation and magnetic susceptibility data taken along the different crystallographic directions evidence a huge crystalline electric field (CEF) induced Ising-type magneto-crystalline anisotropy with a large c-axis moment and a small in-plane moment at low temperature. A detailed CEF analysis based on the magnetic susceptibility data indicates an almost pure |±5/2〉 CEF ground-state doublet with the dominantly |±3/2〉 and the |±1/2〉 doublets at 290 K and 330 K, respectively. At low temperature, we observe a uniaxial antiferromagnetic (AFM) transition at T = 14.7 K with the crystallographic c-direction being the magnetic easy-axis. The magnetic entropy gain up to T reaches almost R ln 2 indicating localised 4 f-electron magnetism without significant Kondo-type interactions. Below T , the application of a magnetic field along the c-axis induces a metamagnetic transition from the AFM to a field-polarised phase at μ H = 0.95 T, exhibiting a text-book example of a spin-flip transition as anticipated for an Ising-type AFM.
我们通过磁学、热学和输运研究来研究 CePdAs 的各向异性磁性质。X 射线衍射证实了四方 ThCrSi 型结构和单晶的高质量。沿着不同晶向测量的磁化和磁化率数据表明，低温下存在巨大的晶场（CEF）诱导的 Ising 型磁晶各向异性，具有大的 c 轴磁矩和小的面内磁矩。基于磁化率数据的详细 CEF 分析表明，在 290 K 和 330 K 时，几乎存在纯的 |±5/2〉CEF 基态双重态，主要是 |±3/2〉和 |±1/2〉双重态。在低温下，我们观察到在 T = 14.7 K 处发生单轴反铁磁（AFM）转变，晶体学 c 方向是磁易轴。磁熵增益到 T 达到几乎 R ln 2，表明存在局域 4f 电子磁性，而没有明显的 Kondo 型相互作用。在 T 以下，沿 c 轴施加磁场会在 μ H = 0.95 T 时从 AFM 诱导出顺磁相变，表现出自旋翻转跃迁的典型例子，如预期的 Ising 型 AFM 一样。
