Every year as the announcement of the Nobel Prize approaches, expectations for potential candidates rise. SAGAWA Masato, the inventor of the world’s strongest permanent magnet, the neodymium magnet, has been often mentioned. His invention is used in a wide range of products, including smartphones, air conditioners and electric vehicles, and is considered a key breakthrough for today’s IT society. How did the idea come about? What drove his research? In January 2025, we talked with Sagawa on the occasion of a lecture at his alma mater, Kobe University.

The Kobe University days that laid the foundation for his research

The invention of the neodymium magnet took place in 1982. At that time, Sagawa was a researcher at Sumitomo Special Metals Co. (now Proterial Metals Ltd.) and was 38 years old. After receiving his master’s degree from Kobe University and his doctorate from Tohoku University, this was his second employer.

He dreamed of becoming a scientist from an early age. When YUKAWA Hideki won the Nobel Prize in physics in 1949, his father explained the newspaper article to him. Inspired by Yukawa’s great achievement, he expressed his goal, saying, “When I grow up, I want to become a scientist and win the Nobel Prize.” During his high school years in Amagasaki, Hyogo Prefecture, he was naturally drawn to science and, on the recommendation of his homeroom teacher, enrolled in the Faculty of Engineering at Kobe University.

“When I enrolled, the liberal arts courses were held in Mikage (Higashinada Ward, Kobe City). I enjoyed being able to study not only science but also various fields such as economics and sociology. It was truly a time when I absorbed a broad education. I was particularly impressed by a sociology class where I heard that humans are social animals.”

At the university, he was also a member of the track and field club. “Although my record in the 400-meter dash was in the 50-second range, which wasn’t particularly remarkable,” he says with a wry smile, “physical fitness is fundamental to research. Both the studies and track activities I engaged in at university have helped lay the foundation for my research life.”

Although his major in the Faculty of Engineering was electrical engineering, his interests gradually shifted, and in graduate school, he immersed himself in research on materials engineering. During the two years of his master’s program, he was greatly influenced by researchers like NAGATA Saburo, who were doing cutting-edge research at the time. “Through my professors, I felt connected to the world. I realized that the lab I was in was a place connected to the global scientific community.”

Setbacks as a researcher and a career change, and then, the invention of the century

At that time, Kobe University did not have a doctoral program, so after completing his master’s degree, he pursued his ambition to conduct research in metallurgical engineering at Tohoku University. However, he struggled to find a clear research direction, and his outcomes, such as papers, were unsatisfactory. “I felt useless as a researcher and lost my confidence,” he recalls. He abandoned the path of remaining in academia and joined Fujitsu Ltd. His first project at the laboratory was the research and development of magnetic materials used in switches and other devices.

 

He says, “The good thing about working for companies was that the goals and deadlines were clear.” Just as he had done in graduate school, he immersed himself in research and gradually began to produce results. Then, about five years after joining the company, he was assigned to develop a “magnet that doesn’t break.” Although he lacked expertise and had no mentors within the company, he began researching on his own and found it fascinating.

“Samarium-cobalt magnets” were considered the strongest at that time. Researchers were competing to enhance the strength of this magnet, and the company’s directive was based on this premise. However, cobalt production was concentrated in a few countries, in Africa and elsewhere, and its price was high.

“I thought, why not use iron, which is an abundant resource? But at that time, all the researchers had already decided that it was impossible. The fact that I had doubts and did experiments was because I was a beginner and young.”

The clue that led to his invention came in 1978, when he heard a presentation at a research meeting in Tokyo. A researcher mentioned that the reason why it is impossible to make a permanent magnet with iron is that the distance between its atoms is too short, and if this could be expanded, it might be possible. It was not the centerpiece of the presentation, but was mentioned briefly, and he thought, “Then, by alloying iron with elements with small atomic radii, like carbon or boron, we can increase the distance between the iron atoms.”

From then, he dedicated his time to experiments in independent research, using after-work hours and holidays. He formally requested to conduct the research at the company, but it was not approved. Seeking a new opportunity, he wrote a letter to Sumitomo Special Metals Co., where the president appreciated his idea, leading to his employment. Shortly after his job change, in 1982, he finally completed the neodymium magnet.

Neodymium, a rare earth element, had not been particularly noted or utilized, but by combining it with iron and boron, the strongest magnet was realized. “I jumped for joy when I made the discovery,” he recalls. The company further improved the research environment, and within three years, they succeeded in mass production.

 Youth leads innovation

Today, neodymium magnets have become indispensable in people’s lives and are also contributing to combating global warming. Motors used in air conditioners, computers and electric vehicles have become more compact, lightweight, and energy-efficient thanks to the use of neodymium magnets. They are also an essential material for enhancing the performance of smartphones.

Sagawa has received countless awards to date. These include many international accolades such as the Queen Elizabeth Prize for Engineering in the United Kingdom, which honors outstanding achievements in the discipline, and the European Inventor Award (in the non-European countries category). Despite these recognitions, his passion for new achievements remains unchanged. Neodymium magnets still have room for improvement in terms of heat resistance, and he continues his research at a company he founded.

“Researchers drive innovation when they are young. As they get older, they strive for the ultimate.”

Sagawa, while expressing these thoughts, implores universities and research institutions, saying: “Give young researchers opportunities. Provide research funding not only to those who are already producing results, but also to those who are in the preliminary stages.” To students and young researchers, he advises: “Value thinking abstractly without being bound by existing logic. This will generate ideas.” The researcher who questioned common sense and achieved breakthroughs now places his hopes on the free thinking of the next generation.

Resume

SAGAWA Masato was born in 1943 in Tokushima Prefecture. After graduating from the Amagasaki Municipal High School, he graduated from the Faculty of Engineering at Kobe University in 1966. He completed the master’s program in electrical engineering at the Graduate School of Engineering in 1968. In 1972, he received his doctorate in metallurgical engineering from the Graduate School of Engineering at Tohoku University. He worked for Fujitsu Ltd. from 1972 to 1982 and for Sumitomo Special Metals Co. from 1982 to 1988.  He was appointed a distinguished invited university professor at Tohoku University in 2019. Currently, he is the president of NDFEB Corporation, which he founded, and works for Daido Steel (Aichi). He has received numerous awards, including the Japan Prize (2012) and the Queen Elizabeth Prize for Engineering (2022).