3 years ago

Topotactic Metal–Insulator Transition in Epitaxial SrFeOx Thin Films

Topotactic Metal–Insulator Transition in Epitaxial SrFeOx Thin Films
Tae Dong Kang, In-Ho Jung, Amit Khare, Tae Won Noh, Seulki Roh, Jungseek Hwang, Dongwon Shin, Woo Seok Choi, Sung Wng Kim, Jaekwang Lee, Minu Kim, Hiromichi Ohta, Tae Sup Yoo
Topotactic phase transformation enables structural transition without losing the crystalline symmetry of the parental phase and provides an effective platform for elucidating the redox reaction and oxygen diffusion within transition metal oxides. In addition, it enables tuning of the emergent physical properties of complex oxides, through strong interaction between the lattice and electronic degrees of freedom. In this communication, the electronic structure evolution of SrFeOx epitaxial thin films is identified in real-time, during the progress of reversible topotactic phase transformation. Using real-time optical spectroscopy, the phase transition between the two structurally distinct phases (i.e., brownmillerite and perovskite) is quantitatively monitored, and a pressure–temperature phase diagram of the topotactic transformation is constructed for the first time. The transformation at relatively low temperatures is attributed to a markedly small difference in Gibbs free energy compared to the known similar class of materials to date. This study highlights the phase stability and reversibility of SrFeOx thin films, which is highly relevant for energy and environmental applications exploiting the redox reactions. Topotactic phase transformation coupled with metal–insulator transition in SrFeOx epitaxial thin films is studied using real-time optical spectroscopy. The oxygen-content-dependent phase transition leads to a pressure–temperature phase diagram of the topotactic transformation. The transformation at relatively low temperatures is ascribed to a markedly small Gibbs free energy difference between the two structurally distinctive phases.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/adma.201606566

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.