Since 2000, he has been studying thin film magnetism and spintronics, more specifically the tunnel magnetoresistance (TMR) effect and spin-transfer torque (STT) in magnetic tunnel junctions (MTJs) and their applications to various devices such as magnetic sensors and magnetoresistive random-access-memory (MRAM). His most important scientific achievements are the development of MgO-based MTJs including CoFeB/MgO/CoFeB-type MTJs and their applications to read heads of hard disk drives and STT-MRAM. For his pioneering contribution to the MgO-based MTJs, he has been awarded or co-awarded more than 20 prizes, including the Asahi Award in 2007. He is IEEE Fellow, Japan Society of Applied Physics (JSAP) Fellow, and Magnetics Society of Japan (MSJ) Fellow. He served as a Program Co-Chair for the 2013 Joint MMM-Intermag Conference, General Chair of 2019 MMM Conference, and a Distinguished Lecturer of IEEE Magnetics Society 2012.