Lee Joonhyuk, Kim Younghak, Cho Jinhyung, Ohta Hiromichi, Jeen Hyoungjeen
Department of Physics, Pusan National University Busan 46241 Korea
Pohang Accelerator Laboratory, Pohang University of Science and Technology Pohang 37673 Korea.
RSC Adv. 2021 Sep 29;11(51):32210-32215. doi: 10.1039/d1ra06378b. eCollection 2021 Sep 27.
Controlling the oxide ion (O) concentration in oxides is essential to develop advanced ionic devices, solid oxide fuel cells, smart windows, memory devices, energy storage devices, and so on. Among many oxides several transition metal (TM)-based perovskite oxides show high oxide ion conductivity, and their physical properties show high sensitivity to the change of the oxide ion concentration. Here, the change in the oxide ion concentration is shown through the overlayer deposition on the SrFeCoO (SFCO) oxygen sponge film. We grew SFCO films followed by the deposition of two kinds of complex oxide films under exactly the same growth conditions, and observed the changes in the crystal structure, valence states, and magnetic ground states. As the NSMO overlayer grows, strong evidence of oxidation at the O K edge is shown. In addition, the Fe feature is revealed, and the electron valence state of Co increased from 3 to 3.25. The oxide ion concentration of SFCO changes during layer growth due to oxidation or reduction due to differences in chemical potential. The present results might be useful to develop advanced ionic devices using TM-based perovskite oxides.
控制氧化物中的氧离子（O）浓度对于开发先进的离子器件、固体氧化物燃料电池、智能窗、存储器件、储能器件等至关重要。在众多氧化物中，几种基于过渡金属（TM）的钙钛矿氧化物表现出高氧离子传导率，并且它们的物理性质对氧离子浓度的变化表现出高灵敏度。在此，通过在SrFeCoO（SFCO）氧海绵薄膜上沉积覆盖层来展示氧离子浓度的变化。我们生长了SFCO薄膜，然后在完全相同的生长条件下沉积两种复合氧化物薄膜，并观察晶体结构、价态和磁基态的变化。随着NSMO覆盖层的生长，在O K边显示出强烈的氧化证据。此外，Fe特征得以揭示，并且Co的电子价态从3增加到3.25。由于化学势的差异导致氧化或还原，SFCO的氧离子浓度在层生长过程中发生变化。目前的结果可能有助于利用基于TM的钙钛矿氧化物开发先进的离子器件。
