You can see the light from stars in the night sky, but that is only a fraction of their total light, because visible light is subject to be absorbed by dust floating in space. Dust absorbs visible and ultraviolet light and re-emits the energy at far-infrared and submillimeter wavelengths. Therefore, by using these wavelengths, we can probe "hidden" activity in the universe, which cannot be traced by visible light. It is known that star-forming activity was more active, and at the same time, the fraction of dust-obscured activity was higher, in the early universe than at present. In this lecture, I will show you how we explore "true" activities of star formation and galaxy evolution through submillimeter observations.

Iron oxides are found as many different phases. Representative phases are hematite (α-Fe₂O₃), also known as red rust, and maghemite (γ-Fe₂O₃). In our laboratory, we developed a rare phase of Fe₂O₃, epsilon iron oxide (ε-Fe₂O₃), which exhibits a strong magnetic anisotropy. Due to its unique magnetic property, this material could be downsized to nanometer-size particles, which is important for magnetic recording. Furthermore, ε-Fe₂O₃ shows high-frequency electromagnetic absorption in the millimeter wave region. This simple iron oxide could contribute to future technologies for big data and the internet of things (IoT). In this lecture, I will introduce the development of functional nanomagnets from basic science to industrial applications.