Yu Hongwu, Okimoto Yoichi, Morita Atsuya, Shimanuki Shuhei, Takubo Kou, Ishikawa Tadahiko, Koshihara Shin-Ya, Minakami Ryusei, Itoh Hirotake, Iwai Shinichiro, Ikeda Naoshi, Sakagami Takumi, Nozaki Mayu, Fujii Tatsuo
Department of Chemistry, Tokyo Institute of Technology, 2-12-1, Meguro, Tokyo 152-8551, Japan.
Department of Physics, Tohoku University, Sendai 980-8578, Japan.
Materials (Basel). 2023 Feb 28;16(5):1989. doi: 10.3390/ma16051989.
An epitaxial film of YbFeO, a candidate for oxide electronic ferroelectrics, was fabricated on yttrium-stabilized zirconia (YSZ) substrate by magnetron sputtering technique. For the film, second harmonic generation (SHG), and a terahertz radiation signal were observed at room temperature, confirming a polar structure of the film. The azimuth angle dependence of SHG shows four leaves-like profiles and is almost identical to that in a bulk single crystal. Based on tensor analyses of the SHG profiles, we could reveal the polarization structure and the relationship between the film structure of YbFeO and the crystal axes of the YSZ substrate. The observed terahertz pulse showed anisotropic polarization dependence consistent with the SHG measurement, and the intensity of the emitted terahertz pulse reached about 9.2% of that emitted from ZnTe, a typical nonlinear crystal, implying that YbFeO can be applied as a terahertz wave generator in which the direction of the electric field can be easily switched.
通过磁控溅射技术在钇稳定氧化锆（YSZ）衬底上制备了作为氧化物电子铁电体候选材料的YbFeO外延薄膜。对于该薄膜，在室温下观察到二次谐波产生（SHG）和太赫兹辐射信号，证实了薄膜的极性结构。SHG的方位角依赖性呈现出四叶状分布，并且几乎与块状单晶中的情况相同。基于SHG分布的张量分析，我们能够揭示YbFeO薄膜的极化结构以及薄膜结构与YSZ衬底晶轴之间的关系。观察到的太赫兹脉冲显示出与SHG测量一致的各向异性极化依赖性，并且发射的太赫兹脉冲强度达到典型非线性晶体碲化锌发射强度的约9.2%，这意味着YbFeO可以用作太赫兹波发生器，其中电场方向可以轻松切换。
