Centre for Advanced Materials, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
J Phys Condens Matter. 2013 Jun 12;25(23):236002. doi: 10.1088/0953-8984/25/23/236002. Epub 2013 May 16.
A detailed microscopic structural study on two single crystalline dilute magnetic oxides, BaTi0.95Fe0.05O(3-δ) with and without perceptible δ, has been carried out. Although it has been reported earlier that varying δ significantly affects high temperature ferromagnetism, the real distribution/redistribution of vacancies and dopant Fe ions inside the 6H hexagonal structure was never probed. This study reveals that oxygen vacancies reduce the dopant Fe(3+) ions to Fe(2+) and mostly accumulate around these Fe(2+) ions. Another distinct trend is the tendency of the dopant Fe ions to get closer instead of being distributed randomly, thereby creating Fe2(2+)O(9-δ') like dimers within the 6H hexagonal unit cell. This experimental observation definitively confirms previous hypotheses based on theoretical models.
对两种单晶稀磁氧化物 BaTi0.95Fe0.05O(3-δ)（有和无明显 δ）进行了详细的微观结构研究。尽管之前有报道称 δ 的变化会显著影响高温铁磁性，但在 6H 六方结构中，空位和掺杂 Fe 离子的实际分布/再分布从未被探测到。这项研究表明，氧空位将掺杂的 Fe(3+)离子还原为 Fe(2+)，并主要聚集在这些 Fe(2+)离子周围。另一个明显的趋势是掺杂的 Fe 离子倾向于靠近而不是随机分布，从而在 6H 六方单元中形成类似于 Fe2(2+)O(9-δ')的二聚体。这种实验观察明确证实了之前基于理论模型的假设。
