Nucleogenic iron charge states in CoO studied by Mössbauer spectroscopy
Nucleogenic iron charge states in CoO studied by Mössbauer spectroscopy
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通过穆斯堡尔光谱研究 CoO 中的成核铁电荷态
DOI：
10.1016/j.jpcs.2004.06.004
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
U. D. Wdowik
中科院分区：
文献类型：
--
作者：
K. Ruebenbauer;U. D. Wdowik
CoO单晶的掺杂量约为40原子。ppm的57Co。穆斯堡尔谱测量与样品取向，温度和降低氧气压力下，即低钴空位浓度。不同的铁电荷状态共存，直到约866 K。在此温度以上观察到混合价态。在1255K以上，由于空穴的迁移率相对于电子的迁移率降低，它逐渐向Fe 2+态演化。空穴迁移率与电子迁移率的比率随着空位浓度的增加而增加，即随着氧压的增加而增加。缺陷在低于866K时排列成簇，留下几乎完美的结构。无反冲分数在923K以上表现出一定的非谐性。
Single crystal of CoO was doped by about 40-at. ppm of57Co. Mössbauer spectra were measured vs. sample orientation, temperature and under reduced oxygen pressure, i.e. for a low cobalt vacancy concentration. Distinctly different iron charge states coexist till about 866K. A mixed-valent state is observed above this temperature. It evolves gradually towards the Fe2+state above 1255K due to the decreasing mobility of holes, as compared to the mobility of the electrons. The ratio of the mobility of holes to the mobility of electrons increases with the increasing vacancy concentration, i.e. with the increasing oxygen pressure. Defects order into clusters below 866K leaving behind almost perfect structure. A recoilless fraction exhibits some anharmonicity above 923K.