Effects of Metal Blending in Random Bimetallic Single-Chain Magnets: Synergetic, Antagonistic, or Innocent

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• 作者：Dr. Yan-Qin Wang ; Dr. Qi Yue and Prof. Dr. En-Qing Gao
• 刊名：Chemistry - A European Journal
• 出版年：2017
• 出版时间：January 18, 2017
• 年：2017
• 卷：23
• 期：4
• 页码：896-904
• 全文大小：4298K
• ISSN：1521-3765

文摘

A family of isomorphous three-dimensional metal–organic frameworks based on bimetallic (FeCo, FeNi, and CoNi) chains with random metal sites have been prepared and magnetically characterized. The solid-solution-type bimetallic materials inherit intrachain ferromagnetic interactions and single-chain-magnet (SCM) behaviors from the homometallic parent materials. Interestingly, different composition dependence of magnetic behaviors has been found. The Fe^II_1−xNi^II_x series (0≤x≤1) show an innocent composition dependence, where the blocking temperature of slow relaxation decreases monotonically as Fe^II is replaced by less anisotropic Ni^II. The Fe^II_1−xCo^II_x series show an unexpected antagonistic blending effect on slow relaxation: blending Fe^II and Co^II tends to depress the spin dynamics, and the bimetallic materials with intermediate composition show significantly lower blocking temperature than both Fe^II and Co^II materials. This is quite the opposite of what happens in the Co_1−xNi_x series, where Co^II and Ni^II seem to have a synergetic effect so that slow relaxation in bimetallic systems can be promoted to higher temperature than both Co^II and Ni^II materials.