Photoinduced phase transition of RbMnFe ( CN ) 6 studied by x-ray-absorption fine structure spectroscopy
Photoinduced phase transition of RbMnFe ( CN ) 6 studied by x-ray-absorption fine structure spectroscopy
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X射线吸收精细结构光谱研究RbMnFe(CN)6光致相变
DOI：
10.1103/physrevb.66.184111
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发表时间：
2002
影响因子：
3.7
通讯作者：
T. Ohta
中科院分区：
文献类型：
--
作者：
T. Yokoyama;H. Tokoro;S. Ohkoshi;K. Hashimoto;K. Okamoto;T. Ohta
用x射线吸收精细结构光谱研究了RbMnFe(CN) 6的光致磁相变。在30 K的可见光（532 nm）照射下，材料发生光致互变异构自旋跃迁。Mn和Fe的k边x射线吸收近边结构谱表明，在相变过程中，Fe三维电子转移到Mn三维能级；Mn的电子态由三价态（d 4，自旋动量S=2）变为二价态（d 5，S=5/2）， Fe的电子态也相应由二价态（d 6，S=0）变为三价态（d 5，S= 1 /2）。用扩展的x射线吸收精细结构分析研究了光致相以及低温和高温相的局部结构。Mn（III）八面体在低温相中表现出明显的Jahn-Teller畸变，其中4个较短键和2个较长键的Mn- n距离分别为1.964 ' 0.008和2.21 ' 0.01 a。高温相的Mn-N距离较长，为2.211′0.006 a，但较短的距离对Mn-N距离的贡献较小。结果还表明- fe - c - n- mn -链的原子构型是共线的，Rb离子位于立方晶格的中心。发现光诱导相在结构和电子上与高温相相同。
Photoinduced magnetic phase transition of RbMnFe(CN) 6 has been investigated by means of x-ray-absorption fine structure spectroscopy. Upon visible-light (532 nm) irradiation at 30 K, the material undergoes the photoinduced tautomeric spin transition. Mn and Fe K-edge x-ray-absorption near-edge structure spectra have clarified that upon the phase transition, a Fe 3d electron is transferred to the Mn 3d level; the electronic state of Mn changes from trivalent (d 4 , spin momentum S=2) to divalent (d 5 ,S=5/2), while the Fe state correspondingly varies from divalent (d 6 ,S=0) to trivalent (d 5 ,S=½). Local structures have been investigated by the extended x-ray-absorption fine-structure analysis for the photoinduced phase as well as for the low- and high-temperature phases. The low-temperature phase shows a significant Jahn-Teller distortion in the Mn(III) octahedron, where the Mn-N distances for four shorter and two longer bonds are 1.964′0.008 and 2.21′0.01 A, respectively. The high-temperature phase gives a longer Mn-N distance of 2.211′0.006 A, although some minor contribution from a shorter distance still remains. It is also revealed that the atomic configuration of the -Fe-C-N-Mn- chain is essentially collinear and that the Rb ions locate at the center of the cubic lattice. The photoinduced phase was found to be structurally and electronically identical to the high-temperature phase.
DOI：
--
发表时间：
2001
期刊：
Phys.Rev.Lett. 86
影响因子：
--
作者：
Takeshi TAYAGAKI;Koichiro Tanaka
通讯作者：
Koichiro Tanaka