Mikhailova Daria, Reichel Phillip, Tsirlin Alexander A, Abakumov Artem M, Senyshyn Anatoliy, Mogare Kailash M, Schmidt Marcus, Kuo Chang-Yang, Pao Chin-Wen, Pi Tun-Wen, Lee Jyh-Fu, Hu Zhiwei, Tjeng Liu Hao
Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Str. 40, D-01187 Dresden, Germany.
Dalton Trans. 2014 Oct 7;43(37):13883-91. doi: 10.1039/c4dt01893a. Epub 2014 Aug 11.
We have realized a reversible structure transformation of one-dimensional 1D K4CdCl6-type Sr3CoMO6 with the Co(2+)/M(4+) cation ordering into the two-dimensional 2D double layered Ruddlesden-Popper structure Sr3CoMO7-δ with a random distribution of Co and M (with M = Ru, Ir) upon increasing the partial oxygen pressure. The combined soft and hard X-ray absorption spectroscopy studies show that under transformation, Co and M cations were oxidized to Co(3+) and M(5+). During oxidation, high-spin Co(2+) in Sr3CoMO6 first transforms into high-spin Co(3+) in oxygen-deficient Sr3CoMO7-δ, and then further transforms into low-spin Co(3+) in fully oxidized Sr3CoMO7 upon further increasing the partial pressure of oxygen. The 1D Sr3CoMO6 compound is magnetically ordered at low temperatures with the magnetic moments lying along the c-axis. Their alignment is parallel for Sr3CoRuO6 and antiparallel for Sr3CoIrO6. The 2D compounds reveal a spin-glass-like behavior related to the random distribution of magnetic cations in the structure.
通过提高氧分压，我们实现了一维1D K4CdCl6型具有Co(2+)/M(4+)阳离子有序排列的Sr3CoMO6向二维2D双层Ruddlesden-Popper结构Sr3CoMO7-δ的可逆结构转变，其中Co和M（M = Ru、Ir）呈随机分布。软硬X射线吸收光谱联合研究表明，在转变过程中，Co和M阳离子被氧化为Co(3+)和M(5+)。在氧化过程中，Sr3CoMO6中的高自旋Co(2+)首先转变为缺氧的Sr3CoMO7-δ中的高自旋Co(3+)，然后在进一步提高氧分压时进一步转变为完全氧化的Sr3CoMO7中的低自旋Co(3+)。一维Sr3CoMO6化合物在低温下呈磁有序，磁矩沿c轴方向。对于Sr3CoRuO6，它们的排列是平行的，而对于Sr3CoIrO6则是反平行的。二维化合物表现出与结构中磁性阳离子随机分布相关的自旋玻璃状行为。
