SCHOOL OF ENGINEERING, TOHOKU UNIVERSITY Driving Force THE POWER TO MAKE TOMORROW INTERVIIEW REPORT
SCHOOL OF ENGINEERING, TOHOKU UNIVERSITY Driving Force THE POWER TO MAKE TOMORROW INTERVIIEW REPORT

By putting out new products into the world,I want to see society become more prosperous. By putting out new products into the world,
I want to see society become more prosperous.

Department of Applied Physics,
Graduate School of Engineering,
Tohoku University.
Shoma Akamatsu REPORT #33

© School of Engineering, Tohoku University

Focusing on sendust alloys discovered at Tohoku University almost 90 years ago, paving the way for their application to thin films.

Cambridge, Massachusetts (Boston, USA). An email from Japan arrived at the inbox of a graduate student studying abroad at Massachusetts Institute of Technology (MIT). The email informed the recipient that he had been awarded the Commendation for Science and Technology by the Minister of Education, Culture, Sports, Science and Technology, the highest award in the student division of the “36th Advanced Technology Awards for Pioneering Creativity.” The recipient was Shoma Akamatsu, a PhD student at the Department of Applied Physics of the Graduate School of Engineering, Tohoku University.

The award recognizes papers written by science and engineering students, young researchers, and engineers in companies and research institutes who have achieved outstanding research results. Mr. Akamatsu received this award for the “Research on Supersoft Sendust Alloy Thin Films for Application to High-sensitivity Quantum Spintronics Magnetic Sensors.”

The sendust alloys used in his research were discovered in 1932 by Professor Emeritus Hakaru Masumoto and Mr. Tatsuji Yamamoto of the Institute for Materials Research, Tohoku University. It was named “sendust” as it was discovered in Sendai and it was easy to pulverize into a powder (dust). Sendust alloys have been used in the tips of magnetic heads of hard disc drives (HDDs) and other parts because such alloys, in certain compositions, exhibit excellent soft magnetic properties (such as losing their magnetization and returning to their original state when the external magnetic field is removed).

Discovered more than 90 years ago, decades have passed without the principles behind sendust alloys being well understood. Mr. Akamatsu says that in his research, he focused anew on the arrangement of atoms (atomic order). He explains, “When sendust alloys were discovered, experiments were repeatedly conducted on the ratios of metals to be compounded, in other words, compositions were changed in different ways. In contrast, I experimented on both the composition and the arrangement. As a result, I discovered that certain rules existed, which I was able to systemize.”

As the title of his research suggests, the goal of Mr. Akamatsu’s research is the development of a highly sensitive quantum spintronics magnetic sensor. Electrons have two properties - “charge” (the source of electricity) and “spin” (the source of magnetism). Focusing on spin, Mr. Akamatsu is aiming to develop a palm-sized, highly sensitive quantum magnetic sensor that detects weak magnetism emitted by the human body. He says, “I chose a sendust alloy as a material for the sensor. In my research, it is necessary to have materials made into nanometer-order thin films. To achieve this, first I had to thoroughly understand the principles behind sendust alloys and explore their potential in applying them to thin films. As I conducted my research with this intention in mind, I was able to achieve the results I got.”

By developing a palm-sized, highly sensitive quantum magnetic sensor, I want to contribute to advancing the understanding of the brain’s workings.

Mr. Akamatsu’s dream of developing a highly sensitive quantum magnetic sensor stems from wanting to “clarify the brain’s workings,” a wish he has had since elementary school. Devices used to understand the brain’s state include electroencephalographs which measure the brain's electrical signals, magnetoencephalographs which measure the magnetic field emitted by the brain (the brain’s magnetic field), and magnetic resonance imaging (MRI) which uses a strong magnet and electromagnetic waves to generate cross-sectional images of the brain. However, these devices have disadvantages. In electroencephalographs, eye blinking causes interference which may be erroneously interpreted, while magnetoencephalographs and MRIs are large, expensive, and can only be used when the patient is at rest. He says, “If I can develop a palm-sized magnetic sensor, it can be incorporated into a simple device of the size of a hat, and much information from the brain can be obtained while it is in an active state during activities such as studying or exercising. There are still many things that are unknown about the brain, such as memory and sleep mechanisms. If we can obtain clearer and more detailed information by developing highly sensitive quantum magnetic sensors, then brain science will also make great advances based on such information. This potential is a huge motivation for my research.”

Mr. Akamatsu says there are still many challenges to overcome before having an actual palm-sized, highly sensitive quantum magnetic sensor. “In the real world, there are all kinds of interference such as electricity, magnetism, and heat. The more sensitive a sensor is, the more interference is mixed into the information. To analyze information with interference mixed in, we must create a kind of AI solely for magnetic analysis, and the development of such an AI is also an important goal for me,” he explains.

According to Mr. Akamatsu, another challenge is the further improvement of the “magnetoresistance ratio.” Most of the devices around us transmit information by exchanging electrical signals. It’s the same with magnetic sensors – the greater the output of a large electrical signal for a smaller magnetism (i.e., the higher the magnetoresistance ratio), the better the magnetic sensor.

He says, “Just like the iPhone which has made people’s lives more convenient and richer, I want to put out new products into society, and see how they enrich society.” This dream, which has not changed since he first entered the School of Engineering, is the driving force behind his research.

School of Engineering, Tohoku University Driving Force, The Power to Make Tomorrow. INTERVIIEW REPORT

Beyond doctoral research, there are ways to contribute to society from universities.

Tohoku University has a program called the "Graduate Program in Spintronics (GP-Spin)" which aims to nurture PhD candidates with a background in spintronics who can flourish with a global perspective. At GP-Spin, in addition to world-class, Tohoku University faculty members, faculty members from educational and research institutions overseas with proven track records also participate in the program to jointly educate students. One characteristic of the program is that students undergo special training in spintronics abroad for a total of six months, for which they must plan for and travel by themselves. Mr. Akamatsu’s studies at MIT fell under GP-Spin training as a student of the program.

He says that the reason he chose to train at MIT was that he “wanted to see for himself the environment at MIT which is one of the top universities in the world, and to learn about the professors and students’ motivations behind their research.” What did he learn and feel during the six months of training? “The lab where I conducted my research concentrated more on physics and principles. Until then, I have been aiming for manufacturing devices and their social implementation, so it was a good experience for me to learn about and focus on principles and physics, which were in a sense, fresh to me. When we were discussing principles, I would share my thoughts which were more about applications, and I received reactions I’d never had such as “Oh, you think about things from such a point of view (that is to say, from the applications point of view).”

Mr. Akamatsu says that another thought occurred to him due to his training at MIT. He says, “I want to contribute more to elevating the research capabilities of Japanese universities.” He explains, “I became more aware of the need to contribute to society not only through manufacturing, but also to Japan by improving technological and scientific capabilities. The reason for this is that I realized MIT and other American universities have structures that bring capital and highly talented individuals together. Students there have a strong sense of advancing to graduate school, obtaining PhDs and contributing to society from universities. On the other hand, in Japan, the reality is that even among the brightest students, only a few go on to obtain their doctorate degrees. I hope my university’s undergraduates and high school students who are interested in engineering and other science-related research and manufacturing will go all the way to obtaining doctorate degrees and be deeply involved in research. I also hope they can find ways to contribute to society from universities.

Experiencing the fun of manufacturing at Exploring-Germination-and-Growth program for young Scientists (EGGS) during high school

Mr. Akamatsu’s first encounter with Tohoku University’s School of Engineering was when he joined the EGGS program during his sophomore year in high school. Science lovers from high schools all over Japan gathered at Tohoku University to deepen their interest in and knowledge of science while experiencing university-level lectures and research firsthand. After finishing the program, he found the process of manufacturing interesting. At the time, he was already aware of spintronics research, so he decided to enter the Department of Electrical, Information and Physics Engineering of Tohoku University’s School of Engineering with the hope of “using cutting-edge physics to create revolutionary devices that are completely different from conventional ones.” He says, “My advice is not deciding on a career path just because you’re interested in something. I recommend experiencing something in some form or another, such as the EGGS program I joined. That’s because you’ll never know if something is truly right for you until you try it.”

Mr. Akamatsu, who was admitted to Tohoku University through the university’s admissions office process (involving an examination and other requirements), was given the chance to study abroad for two weeks before the university’s entrance ceremony in March. He joined Tohoku University’s “Pre-Entrance Training Program,” a program originated by the university and the first of its kind among public universities in Japan. Through this program, he studied at University of California, Riverside in the United States, and was able to speak in English and experience other cultures through university classes, interactions with local students, and a homestay.

Mr. Akamatsu, who went to Seattle and Taiwan as an undergraduate, and attended academic conferences held in Europe after entering graduate school, says that “Tohoku University offers many study-abroad programs, and their support for such programs is comprehensive.” He explains, “The lab I belonged to actively encouraged me to join academic conferences, even the ones abroad. Interactions with overseas researchers not only made me recognize that there are people conducting research in the same field in other countries, but they also gave me fun and new experiences such as excitedly discussing common topics in English.”

While most of his days are focused on research, Mr. Akamatsu often relaxes in saunas in the middle of nature on his days off. “I’m often surrounded by equipment for experiments and computers in my everyday life, so on my days off, I try to stay away from those things as much as possible. The Aobayama Campus which houses the School of Engineering is rich in nature, and I like the fact that I can walk all the way to the Faculty of Agriculture for a change in scenery,” he says.