B-Cation Order Control of Magnetism in the 1322 Perovskite CaCu3Fe2Nb2O12

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• 作者：Mark S. Senn ; Wei-tin Chen ; Takashi Saito ; Susana Garc铆a-Mart铆n ; J. Paul Attfield ; Yuichi Shimakawa
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：August 26, 2014
• 年：2014
• 卷：26
• 期：16
• 页码：4832-4837
• 全文大小：546K
• ISSN：1520-5002

文摘

Cation ordering in the 1322 perovskite CaCu₃Fe₂Nb₂O₁₂ has been investigated by synchrotron X-ray diffraction structure analysis, high-resolution electron microscopy, and magnetic measurements. All of the samples have full 1:3 ordering of Ca and Cu cations at the perovskite A-sites, but the Fe and Nb cations at the B sites show different degrees of ordering depending on the synthesis conditions. A slow-cooled sample has almost complete rock-salt-type 1:1 cation ordering at the B sites, but a rapidly cooled sample has no long-range B-cation arrangement. The ordered compound shows a large saturated magnetization (5.7 渭_B/formula unit (fu)) below 170 K due to the ferrimagnetism of the A鈥?site Cu²⁺ and B-site Fe³⁺ spins, whereas the B-site disordered form has a small magnetization (<1 渭_B/fu at 5 K). The degree of B-site cation order thus controls the magnetic behavior of 1322 CaCu₃Fe₂Nb₂O₁₂ perovskites.