Material Development for reversible control of magnetism and superconductivity upon photoirradiation

At Keio University, the Inorganic Materials Chemistry Laboratory focuses on two main research projects: “Fabrication of photofunctional materials,” and “development of diamond electrochemical sensors".
"The words “photofunctional materials” may be difficult to imagine. Let us think about a solar panel. When sunlight shines the panel like this, electricity is generated. More generally, a photofunctional material can be defined as the material shows some specific function when absorbing light. For easy understanding, please imagine a bean-paste dumpling, which we can find bean-paste inside and dough outside. In our photofunctional materials, bean-paste is a magnet and dough is a molecule reacts to light. In other words, our photofunctional materials are double-layered structure. When absorbing light, a chemical property of dough changes. This change transfers to bean-paste, which results in a property change of whole dumpling."
Thus far a wide variety of photofunctional materials have been developed, such as a solar panel. In particular, reversibly photocontrollable magnetic and superconducting materials are expected to be applied to next-generation electronics. For example, if a photocontrollable magnetic material is used as a storage medium such as a hard disk, information could be processed by inducing change in magnetic properties upon photoirradiation, which would increase the read-out speed dramatically compared to a conventional hard disk.
"Our photocontrollable magnet is nano-sized; the idea is that it is possible to store information in an individual magnet. The new and interesting features using nanosheets is a huge number of combinations; there is a lot of magnetic nanosheets, and a lot of photoresponsive nanosheets. Really, there is a great variety of combinations. In addition, as their name, nanosheets are extremely thin – about 1 nm. So, composite materials made by stacking nanosheets are also extremely thin, which ultimately means that a device could be more compact and integrated."
If nano-sized magnetic materials can be integrated and arranged efficently, it would lead to the development of new storage media for broadband data processing. Thus far, there is a limitation on operating temperature, and photoinduced changes in magnetic properties are still small. So, Dr. Yamamoto focuses on solving these problems.
Looking ahead, the Inorganic Materials Chemistry Laboratory is investigating efficient photofunctional magnetic materials to expand the possibility of such materials for next-generation electronics.