Nawa Kazuhiro, Murasaki Ryo, Itoh Shinichi, Saito Hiraku, Nojiri Hiroyuki, Dela Cruz Clarina, Okuyama Daisuke, Yoshida Masahiro, Ueta Daichi, Yoshizawa Hideki, Sato Taku J
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Sendai 980-8577, Japan.
Institute of Materials Structure Science (IMSS), High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan.
J Phys Condens Matter. 2024 Sep 6;36(49). doi: 10.1088/1361-648X/ad7182.
Pyrochlore magnets have attracted interest as systems for realizing critical phenomena, rich magnetic structures, associated topological band structures, and nontrivial quantum phases. NaCo(CO)Cl is a pseudospin-1/2 antiferromagnet in which the Coions form a pyrochlore network. Its structural and magnetic properties were investigated using magnetization, heat capacity, ESR, single-crystal x-ray diffraction, powder neutron diffraction and powder inelastic neutron scattering. Magnetization and heat capacity measurements indicated a ground-state doublet, which is regarded as pseudospin 1/2, dominated the magnetic properties at low temperatures, with a magnetic exchange of 9.6 K. As the temperature decreases, a magnetic transition is observed at 1.6 K, which is confirmed to be an all-in-all-out magnetic order. The crystal field excitations observed by inelastic neutron scattering experiments indicated the Ising nature of the ground-state doublet. This thorough study revealed that NaCo(CO)Cl can be regarded as a pseudospin-1/2 pyrochlore lattice antiferromagnet with dominant Ising-type interactions.
烧绿石磁体作为实现临界现象、丰富磁结构、相关拓扑能带结构和非平凡量子相的体系而备受关注。NaCo(CO)Cl是一种赝自旋-1/2反铁磁体，其中Co离子形成烧绿石网络。利用磁化强度、热容、电子顺磁共振、单晶X射线衍射、粉末中子衍射和粉末非弹性中子散射对其结构和磁性进行了研究。磁化强度和热容测量表明，基态双重态（被视为赝自旋1/2）在低温下主导磁性，磁交换为9.6 K。随着温度降低，在1.6 K处观察到磁转变，经证实为全进全出磁序。非弹性中子散射实验观察到的晶体场激发表明基态双重态具有伊辛性质。这项深入研究表明，NaCo(CO)Cl可被视为具有主导伊辛型相互作用的赝自旋-1/2烧绿石晶格反铁磁体。
