[3Fa01-05] Surface Engineering/Thin Film

[3Fa04] Hydrogen-induced changes in electrical conduction properties of perovskite SmNiO₃ thin film

*Ikuya Matsuzawa¹, Takahiro Ozawa¹, Azusa Hattori², Hidekazu Tanaka², Katsuyuki Fukutani^1,3 (1. Institute of Industrial Science, the University of Tokyo, 2. SANKEN, Osaka University, 3. Japan Atomic Energy Agency)

The perovskite ReNiO₃ (Re=rare-earth) is known to exhibit a metal-insulator transition (MIT) with temperature change. Furthermore, it was recently reported that hydrogenation increases the electrical resistance of SmNiO₃ by approximately eight orders of magnitude at room temperature. The purpose of this study is to elucidate this mechanism, but the relationship between hydrogen concentration and electrical resistance, which is necessary first, is not yet understood. To investigate this relationship, hydrogenation experiments by exposure to atomic hydrogen, electrical resistivity measurements, and hydrogen concentration measurements by nuclear reaction analysis were performed in situ on SmNiO₃ thin films. These results contrast starkly with the model believed so far. We previously conducted the same experiments on NdNiO₃. The similarities and differences are discussed in comparison with the results.