Klie R F, Zheng J C, Zhu Y, Varela M, Wu J, Leighton C
Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60657, USA.
Phys Rev Lett. 2007 Jul 27;99(4):047203. doi: 10.1103/PhysRevLett.99.047203. Epub 2007 Jul 25.
LaCoO3 exhibits an anomaly in its magnetic susceptibility around 80 K associated with a thermally excited transition of the Co3+-ion spin. We show that electron energy-loss spectroscopy is sensitive to this Co3+-ion spin-state transition, and that the O K edge prepeak provides a direct measure of the Co3+ spin state in LaCoO3 as a function of temperature. Our experimental results are confirmed by first-principles calculations, and we conclude that the thermally excited spin-state transition occurs from a low to an intermediate spin state, which can be distinguished from the high-spin state.
LaCoO₃在80K左右的磁化率出现异常，这与Co³⁺离子自旋的热激发跃迁有关。我们表明，电子能量损失谱对这种Co³⁺离子自旋态跃迁敏感，并且O K边预峰可直接测量LaCoO₃中Co³⁺自旋态随温度的变化。我们的实验结果得到了第一性原理计算的证实，并且我们得出结论，热激发自旋态跃迁发生在从低自旋态到中间自旋态，这可以与高自旋态区分开来。
