The Mn2+/Mn3+ state of La0.7Ce0.3MnO3 by oxygen reduction and photodoping
The Mn2+/Mn3+ state of La0.7Ce0.3MnO3 by oxygen reduction and photodoping
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DOI：
10.1088/0953-8984/26/4/045502
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发表时间：
2013-10
期刊：
影响因子：
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通讯作者：
A. Thiessen;Elke Beyreuther;S. Grafstrom;Kathrin Dorr;Robert Werner;R. Kleiner;D. Koelle;Lukas M. Eng
中科院分区：
文献类型：
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作者：
A. Thiessen;Elke Beyreuther;S. Grafstrom;Kathrin Dorr;Robert Werner;R. Kleiner;D. Koelle;Lukas M. Eng
在过去的十年中，铈掺杂LaMnO3作为电子掺杂的对偶物被广泛讨论，在光激发下，用x射线光电发射光谱分析了它们的锰价。对La0.7Ce0.3MnO3 （LCeMO）薄膜在黑暗和光照条件下Mn 3s交换分裂的对比分析清楚地表明，氧还原和光照都能使Mn价态向2+/3+混合状态降低，而不受薄膜厚度和CeO2偏析程度的影响。讨论了从光导SrTiO3衬底向载流子寿命在几十秒范围内的Mn eg带注入电荷和薄膜内电子-空穴对的本征产生作为Mn价移和随后的电子掺杂的两个可能来源。
Films of cerium-doped LaMnO3, which has been intensively discussed as an electron-doped counterpart to hole-doped mixed-valence lanthanum manganites during the past decade, were analyzed by x-ray photoemission spectroscopy with respect to their manganese valence under photoexcitation. The comparative analysis of the Mn 3s exchange splitting of La0.7Ce0.3MnO3 (LCeMO) films in the dark and under illumination clearly shows that both oxygen reduction and illumination are able to decrease the Mn valence towards a mixed 2+/3+ state, independently of the film thickness and the degree of CeO2 segregation. Charge-injection from the photoconductive SrTiO3 substrate into the Mn eg band with carrier lifetimes in the range of tens of seconds and intrinsic generation of electron–hole pairs within the films are discussed as two possible sources of the Mn valence shift and the subsequent electron doping.