July 13, 2021
Keio University
Kentaro Ogata (second-year master's student) and Yusuke Nakayama (second-year master's student) of the Graduate School of Science and Technology, and Associate Professor Hideo Kaiju of the Faculty of Science and Technology, all from Keio University, in collaboration with Professor Gang Xiao of the Department of Physics at Brown University, 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 155%. This time, by focusing on "voltage," the team achieved the world's largest change rate of 332%. 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, high-sensitivity magnetic sensors and magnetic memories based on capacitance detection.
The results of this research were published in "Scientific Reports" (online, Nature Publishing Group) on July 12 (UK time).
Please see below for the full press release.