Synthesis of High-Entropy Layered Oxide Epitaxial Thin Films: LiCr<sub>1/6</sub>Mn<sub>1/6</sub>Fe<sub>1/6</sub>Co<sub>1/6</sub>Ni<sub>1/6</sub>Cu<sub>1/6</sub>O<sub>2</sub>
Kaidong Wang, Kazunori Nishio, Koji Horiba, Miho Kitamura, Kurei Edamura, Daisuke Imazeki, Ryo Nakayama, Ryota Shimizu, Hiroshi Kumigashira, Taro Hitosugi
Abstract
High-entropy oxides are emerging materials with unique functionalities. However, while various bulk-type high-entropy oxides have been developed, limited research has been pursued for high-entropy oxide thin films. In this paper, we report the synthesis of LiCr1/6Mn1/6Fe1/6Co1/6Ni1/6Cu1/6O2 epitaxial thin films with a layered rocksalt structure via the pulsed laser deposition technique. We obtained a single-phase epitaxial thin film by tuning the laser fluence and substrate temperature. In addition, we fabricated a thin-film-type solid-state battery with the epitaxial thin film as a positive electrode. The battery exhibited stable operation. The results of this study provide a platform for synthesizing high-entropy oxide epitaxial thin films with the layered rocksalt structure.