Topotactic oxidative and reductive control of the structures and properties of layered manganese oxychalcogenides.
Topotactic oxidative and reductive control of the structures and properties of layered manganese oxychalcogenides.
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DOI：
10.1021/ja073048m
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发表时间：
2007-09
影响因子：
15
通讯作者：
G. Hyett;N. Barrier;S. Clarke;J. Hadermann
中科院分区：
文献类型：
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作者：
G. Hyett;N. Barrier;S. Clarke;J. Hadermann
采用氧化和还原两种方法对层状氧硫属化合物Sr_4Mn_3O_（7.5）Cu_2CH_2（CH=S，Se）的组成、结构和磁性进行了拓扑改性。这些Mn3+化合物由交替的钙钛矿型锶锰氧化物板组成，所述钙钛矿型锶锰氧化物板由反萤石型铜硫属化物层隔开，并且在钙钛矿板的中心层中本质上是氧化物缺陷的。该系统是钙钛矿相关化合物的不寻常的例子，其可以拓扑地被氧化，并通过从结构的氧化物缺陷部分脱嵌氧而被还原。该化合物表现出反铁磁有序的锰磁矩在外层的钙钛矿板，而其他时刻，在中心层，表现出自旋玻璃样的行为。氟化具有增加反铁磁有序温度和有序矩大小的作用，而还原通过引入化学无序来破坏磁性长程有序，从而导致锰氧化物板中磁相互作用的进一步无序和挫败。
Topotactic modification, by both oxidation and reduction, of the composition, structures, and magnetic properties of the layered oxychalcogenides Sr4Mn3O7.5Cu2Ch2 (Ch=S, Se) is described. These Mn3+ compounds are composed of alternating perovskite-type strontium manganese oxide slabs separated by anti-fluorite-type copper chalcogenide layers and are intrinsically oxide deficient in the central layer of the perovskite slabs. The systems are unusual examples of perovskite-related compounds that may topotactically be both oxidized by fluorination and reduced by deintercalation of oxygen from the oxide-deficient part of the structure. The compounds exhibit antiferromagnetic ordering of the manganese magnetic moments in the outer layers of the perovskite slabs, while the other moments, in the central layers, exhibit spin-glass-like behavior. Fluorination has the effect of increasing the antiferromagnetic ordering temperature and the size of the ordered moment, whereas reduction destroys magnetic long-range order by introducing chemical disorder which leads to both further disorder and frustration of the magnetic interactions in the manganese oxide slab.