Determination of ground state and magnetic correlations in a quasi-one dimensional spin chain iridate Ca3CoIrO6 using neutron diffraction

Ca3CoIrO6 is a quasi-one-dimensional columnar spin-chain iridate with alternately arranged face-sharing IrO6 octahedra and CoO6 trigonal prisms along the c-axis of the structure. This compound, surprisingly, unlike its isostructural counterparts Ca3Co2O6 and Ca3CoRhO6, does not exhibit partially disordered antiferromagnetic (PDA) structure. While, the combined bulk dc, ac magnetic susceptibilities, specific heat, and isothermal remanent magnetization measurements strongly infer only spin-glass-like freezing transition at ~30 K without any signature of PDA characteristics. The zero-field µSR investigations unravel the coexistence of intrachain ferromagnetic long-range ordering below 100 K and the glassy magnetic transition below 30 K. At this point, detection of true magnetic ground state as well as the ground state Ir- and Co-spin configurations of this system is elusive, thereby warranting microscopic magnetic investigation to authenticate the nature of magnetic ordering and short-range magnetic correlations and we therefore proposed neutron diffraction study of Ca3CoIrO6 on WISH.

Ca3CoIrO6是一种准一维（quasi-one-dimensional）柱状自旋链铱酸盐，其结构沿c轴方向交替排列着共面的IrO6八面体和CoO6三角棱柱。令人意外的是，与同构化合物Ca3Co2O6和Ca3CoRhO6不同，该化合物未表现出部分无序反铁磁（partially disordered antiferromagnetic, PDA）结构。然而，结合体直流、交流磁化率、比热及等温剩余磁化强度的测量结果强烈表明，该化合物仅在约30 K时发生类自旋玻璃冻结转变，且无任何PDA特征的迹象。零场μ子自旋弛豫（μSR）研究揭示，链内铁磁长程有序在100 K以下存在，同时玻璃态磁转变在30 K以下共存。目前，该体系真实磁基态的探测以及Ir和Co自旋基态构型的确定仍不明确，因此需通过微观磁学研究来验证磁有序的本质及短程磁关联，为此我们建议在WISH装置上对Ca3CoIrO6进行中子衍射研究。