Spin crossover, structural change, and metallization in NiAs-type FeO at high pressure
Spin crossover, structural change, and metallization in NiAs-type FeO at high pressure
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DOI：
10.1103/physrevb.84.134417
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发表时间：
2011-10
影响因子：
3.7
通讯作者：
Haruka Ozawa;K. Hirose;K. Ohta;H. Ishii;N. Hiraoka;Y. Ohishi;Y. Seto
中科院分区：
文献类型：
--
作者：
Haruka Ozawa;K. Hirose;K. Ohta;H. Ishii;N. Hiraoka;Y. Ohishi;Y. Seto
利用X射线发射光谱（XES）和X射线衍射（XRD）相结合的方法，研究了高压下NiAs（B8）型Fe${}{0.96}$O（以下简称FeO）中铁的高自旋向低自旋的转变. XES光谱显示B8型FeO在300 K时的自旋损失约高于119 GPa，与120 GPa附近的2.5%体积减少一致。高温XRD研究还表明，在相同的压力条件下，在1560\char21{}1780 K下，类似的体积减小。而FeO的晶体结构仍然是B8型通过这样的体积减少，Fe和O的原子排列的变化从反到正常的NiAs形式与$c$/$a$轴比显着降低。最近的电阻测量，这些表明，铁自旋交叉，逆正态结构的变化，绝缘体-金属过渡同时发生在B8 FeO约120 GPa。
We report high-spin to low-spin crossover of iron in NiAs (B8)-type Fe${}_{0.96}$O (FeO hereafter) at high pressure by a combination of in-situ x-ray emission spectroscopy (XES) and x-ray diffraction (XRD) measurements. The XES spectra show a loss of spin in B8-type FeO approximately above 119 GPa at 300 K, consistent with the \ensuremath{\sim}2.5% volume reduction around 120 GPa. The high-temperature XRD study also demonstrates a similar volume decrease at 1560\char21{}1780 K under the same pressure condition. While the crystal structure of FeO remains to be B8 type across such volume reduction, the atomic arrangements of Fe and O change from inverse to normal NiAs form with considerable decrease in $c$/$a$ axial ratio. With recent electrical resistance measurements, these suggest that iron spin crossover, inverse-normal structural change, and insulator-metal transition occur concurrently in B8 FeO around 120 GPa.