Study on spin configuration in photoresponsive iron mixed-valence complexes by Mössbauer spectroscopy
Study on spin configuration in photoresponsive iron mixed-valence complexes by Mössbauer spectroscopy
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穆斯堡尔谱研究光响应铁混价配合物的自旋构型
DOI：
10.1007/s10751-013-0934-2
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发表时间：
2014
影响因子：
--
通讯作者：
N. Kojima
中科院分区：
文献类型：
--
作者：
A. Okazawa;J. Yoshida;N. Kida;I. Kashima;W. Murata;M. Enomoto;N. Kojima
我们研究了一系列光响应二硫代草酸根 (dto) 桥联铁混合价络合物 (SP-R)[FeIIFeIII(dto)3]（SP-R = R 取代的吡啶并螺吡喃阳离子；R = Me、Et 和 Pr；分别缩写为 1Me、1Et 和 1Pr）的磁性。至于我们之前的报告，1Me 和 1Et 分别显示了 TC= 25 & 8 K 和 22 & 5 K 时的两步连续铁磁转变。然而，1E的磁化率没有磁滞现象，而1Me则在75 K左右经历电荷转移相变，并存在热磁滞。为了阐明它们的两步转变，我们测量了1Et的57Fe穆斯堡尔谱。在磁有序态和顺磁态下观察到了 HTP 中 FeII(S= 2) 和 FeIII(S= 1/2) 的光谱，并揭示了只有 HTP 在高达 5 K 的温度范围内存在。结果与 1Pr 的结果一致，其中在 TC= 10 K 时发生一次铁磁相变。57Fe 穆斯堡尔谱有助于阐明后续磁相变的起源。这些系统。
We have investigated magnetic properties in a series of photoresponsive dithiooxalato (dto)-bridged iron mixed-valence complexes, (SP-R)[FeIIFeIII(dto)3] (SP-R = R-substituted pyridospiropyran cation; R = Me, Et, and Pr; abbreviated as1Me,1Et, and1Pr, respectively). As for our previous reports,1Meand1Etshow two-step succeeding ferromagnetic transitions atTC= 25 & 8 K and 22 & 5 K, respectively. However,1Ethas no hysteresis in the magnetic susceptibility, while1Meundergoes the charge transfer phase transition with thermal hysteresis around 75 K. To elucidate the two-step transitions of them, we measured57Fe Mössbauer spectra of1Et. The spectra of FeII(S= 2) and FeIII(S= 1/2) in the HTP were observed in the magnetically ordered state as well as the paramagnetic state, and revealed that only HTP exists in a temperature range up to 5 K. The result is consistent with that of1Pr, where one ferromagnetic phase transition occurs atTC= 10 K.57Fe Mössbauer spectroscopy is useful to clarify the origin of the succeeding magnetic transition for these systems.