Hoffmann Martin, Antonov Victor N, Bekenov Lev V, Kokko Kalevi, Hergert Wolfram, Ernst Arthur
Institute for Theoretical Physics, Johannes Kepler University Linz, Altenberger Straße 69, 4040 Linz, Austria.
J Phys Condens Matter. 2018 Aug 1;30(30):305801. doi: 10.1088/1361-648X/aacb8d. Epub 2018 Jun 11.
Oxygen vacancies can be of utmost importance for improving or deteriorating physical properties of oxide materials. Here, we studied from first-principles the electronic and magnetic properties of oxygen vacancies in the double perovskite SrFeMoO (SFMO). We show that oxygen vacancies can increase the Curie temperature in SFMO, although the total magnetic moment is reduced at the same time. We found also that the experimentally observed valence change of the Fe ions from 3+ to 2+ in the x-ray magnetic circular dichroism (XMCD) measurements is better explained by oxygen vacancies than by the assumed mixed valence state. The agreement of the calculated x-ray absorption spectra and XMCD results with experimental data is considerably improved by inclusion of oxygen vacancies.
氧空位对于改善或恶化氧化物材料的物理性质可能极为重要。在此，我们从第一性原理出发研究了双钙钛矿SrFeMoO（SFMO）中氧空位的电子和磁性性质。我们表明，氧空位可提高SFMO的居里温度，尽管同时总磁矩会降低。我们还发现，在x射线磁圆二色性（XMCD）测量中实验观察到的Fe离子价态从3+变为2+，用氧空位来解释比用假定的混合价态更好。通过纳入氧空位，计算得到的x射线吸收光谱和XMCD结果与实验数据的吻合度得到了显著提高。
