NIMS Award 2018 Winners
|Dr. Masato SagawaAdvisor for Daido Steel Co., Ltd.
Title:Invention and practical application of neodymium magnets
Research field: Permanent magnet materials
|Dr. Terunobu MiyazakiProfessor Emeritus, Tohoku University
Title: Development of tunneling magnetoresistance elements capable of generating giant magnetoresistance at room temperature and application thereof to spintronics devices
Research field: Spintronics, magnetic materials
Research summary and Impact on the academic and industrial sectors
Dr. Masato Sagawa
Dr. Sagawa invented neodymium (Nd) magnets—the world’s strongest magnets—and developed a method of mass-producing anisotropic magnets through a powder metallurgy process, which quickly enabled industrial production of the Nd magnets. The use of these magnets enabled the development of smaller and lighter electronic devices, such as hard disk drives, and enabled the development of hybrid and electric vehicles. Dr. Sagawa independently discovered Nd-Fe-B-based magnetic alloys before going to work for Sumitomo Special Metals in the early 1980s. After obtaining permission to launch a special project from the manager of the company at that time, Dr. Sagawa developed the world’s strongest Nd-Fe-B-based magnet. He then applied for a patent under the name of Sumitomo Special Metals in 1982 and published the approved patent in 1983. The development of Nd sintered magnets was revolutionary not only because their magnetic fields were stronger than those of the previously strongest Sm-Co-based permanent magnets, but also because they are composed mainly of abundant elements: Fe, which is abundant in nature, and Nd, which is a relatively abundant rare-earth element. The discovery of Nd magnets was also groundbreaking because it defied the common belief that cobalt is a requisite ingredient in permanent magnets and completely resolved the issue of the limited availability of magnet ingredient resources. In addition, the discovery was academically significant due to the fact that the Nd magnet represents the world’s first discovery of a highly magnetic tetragonal compound. Nd magnets remain the world’s strongest 35 years after their invention, and their applications, which now include electric vehicles and robotics, continue to grow.
[Impact on the academic and industrial sectors]
Dr. Sagawa succeeded in achieving industrial application of the anisotropic Nd magnet after obtaining a basic patent for the invention of the magnet in 1982. He promoted basic research on Nd magnets by actively supplying Nd-Fe-B magnet samples to other academic researchers around the world. This effort greatly contributed to advances in materials science focusing on permanent magnets. Sumitomo Special Metals began commercial production of the Nd sintered magnet product NEOMAX in 1985. Production of NEOMAX—the most powerful permanent magnet in the world which can be manufactured using inexpensive raw materials—rapidly increased as the range of its applications expanded. Approximately 70,000 tons of NEOMAX were estimated to have been produced worldwide in 2015. Used in hard disk spindle motors and head actuators, Nd magnets have become indispensable components of modern data storage technologies. More recently, Nd magnets have been used in the motors and generators of hybrid and electric vehicles, wind power generation, energy-efficient air conditioners and the drive units of nursing care robots. The use of these magnets for these purposes is expected to continue growing. Thus, society has benefited immensely from Nd magnets.
Dr. Terunobu Miyazaki
A ferromagnetic tunnel junction element is a triple-layered structure composed of two ferromagnetic layers sandwiching an insulating layer. Tunneling resistance in this element changes in response to differences in magnetic orientation between the two ferromagnetic layers (i.e., the tunneling magnetoresistance (TMR) effect). Although the TMR effect was first reported as early as the 1960s, observations prior to Dr. Miyazaki’s pioneering research on TMR elements at Tohoku University were limited to the detection of subtle TMR at extremely low temperatures. In 1995, Dr. Miyazaki observed a giant TMR effect at room temperature for the first time in the world using triple-layered (Fe/alumina/Fe composition) tunnel junction elements. This success triggered the first public interest in the practical application of TMR elements. After demonstrating the successful operation of TMR elements at room temperature, Dr. Miyazaki continued his TMR element R&D by conducting many joint research projects with researchers in Japan and overseas and assuming leadership of collaborative research between industry and academia. His contributions were crucial in achieving the application of TMR elements to spintronics devices. These research efforts increased public awareness of spintronics as a new electronics field, and led to the creation of new industries that apply ferromagnetic tunnel junction elements to the manufacture of hard disk read heads, magnetic random access memories and other devices. Dr. Miyazaki’s efforts greatly contributed to society by advancing and popularizing spintronics.
[Impact on the academic and industrial sectors]
Dr. Miyazaki’s observation of a magnetoresistance effect at room temperature using TMR elements had a profound impact on the academic and industrial sectors. TMR elements were put into practical use in the development of high-sensitivity read heads for hard disk drives (HDDs), which were commercialized in 2001 and still in use today. The improved performance of TMR read heads enabled an increase in HDD recording density, from tens of Gbit/in2 before 2001 to 1 Tbit/in2 today, greatly increasing the storage capacity of HDDs, which now serve as vital infrastructure for our advanced information society. TMR elements are also used as memory cells in MRAM devices, a promising candidate for next-generation non-volatile memory. The global R&D effort to develop these technologies has its roots in Dr. Miyazaki’s discovery. The room temperature TMR effect has been applied in a wide variety of engineering and scientific research projects, such as exploration of high spin polarization materials and magnetically anisotropic materials and spin torque generated by spin transport. These research projects were highly valued by academic and industrial groups and won many awards, including the Asahi Prize, the JSAP (Japan Society of Applied Physics) Award and the American Physical Society Award. As a longtime member of the Tohoku University faculty, Dr. Miyazaki has provided academic advice to many students and instructed many young researchers in the magnetism and spintronics field. He has contributed greatly to maintaining Japan’s high research standards in this field.
2017 Award Ceremony
（October 4th, 2017 at Tsukuba International Congress Center）
2017 Award Winning-lecture
NIMS WEEK 2018 Academic Symposium
will be held on October 15th, Monday at Tokyo International Forum