2022/05/17
Keio University
Kenta Sato (a second-year master's student at the Graduate School of Science and Technology, Keio University) and Associate Professor Hideo Kaiju of the university's Faculty of Science and Technology, in collaboration with Principal Researcher Hiroaki Sukegawa of the National Institute for Materials Science and Professor Gang Xiao of Brown University's Department of Physics, have successfully observed the world's largest tunnel magnetocapacitance (TMC) effect and elucidated its mechanism. The TMC effect is a phenomenon in which capacitance (the amount of electricity that can be stored) changes in response to a magnetic field. This phenomenon is observed in magnetic tunnel junctions, which consist of a thin insulating layer sandwiched between two magnetic layers. The capacitance change rate, which indicates magnetic sensitivity, had a previous maximum of 332%. This time, by "innovating the insulating layer" and "applying voltage," they achieved a change rate of 426%, the largest in the world. Furthermore, they elucidated the mechanism using a dielectric theory that incorporates quantum mechanics and statistical theory. This achievement paves the way for the creation of new, highly sensitive magnetic sensors and magnetic memory based on capacitance detection.
The results of this research were published in "Scientific Reports" (online, Springer Nature group) on May 16 (UK time).
Please see below for the full press release.