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Volume 7: Hideo Ohno "Development of Ferromagnetic Semiconductors"

Hideo Ohno
Professor, Tohoku University

There is a field of engineering called spintronics that aims to exploit both the charge and spin of electrons.

Traditionally, the electron’s ability to carry charge has been utilized in logic circuits, while its ability to act as a magnet has been utilized in hard drives. Spintronics combines these two properties of the electron to develop brand new materials and devices.

Hideo Ohno pioneered the field of spintronics. Since the latter half of the 1980s he performed basic research in the field and developed ferromagnetic semiconductors, which possess the characteristics of both semiconductors and magnets. His work generated international interest, and today there are many scientists around the world conducting studies on the practical use of magnetic semiconductors.

In magnetic semiconductors, magnetism can be controlled electrically by utilizing the properties of a semiconductor as an electrical device. This has led to the creation of non-volatile memory with very low power consumption, much lower than what was possible previously. Non-volatile memory is a type of computer memory that does not require power to retain stored information; hard drives are an example of non-volatile memory. Before magnetic semiconductors, non-volatile memory required power for processes such as melting a component’s fuse with electric current or maintaining charge on a floating gate transistor surrounded by an insulator. A magnetic semiconductor, however, can retain positive and negative charges within the material itself, and by controlling this electrical property, it is also possible to control the magnetism of the material.

Utilizing the properties of both charge and spin, magnetic semiconductors have also been used to develop a new kind of integrated circuit that can perform calculations and store information as a single system.  The considerably higher performance and lower power consumption of this system compared to conventional integrated circuits has revolutionized the design and production methods of integrated circuits.

Integrated circuit systems with zero standby energy consumption, made possible by Ohno, have the potential to become the world standard. They are certain to bring about fundamental changes to integrated circuits, which in turn form the basis of the information and communication tools used in society, as well as various industrial products.

Hideo Ohno Profile

2010 – Present Director, Center for Spintronics Integrated Systems, Tohoku University
2004 – 2010 Director, Laboratory for Nanoelectronics and Spintronics (affiliated with RIEC), Tohoku University
1995 – Present Professor, Research Institute of Electrical Communication (RIEC), Tohoku University
1994 – 1995 Professor, School of Engineering, Tohoku University
1988 – 1990 Visiting Scientist, IBM Thomas J. Watson Research Center
1983 – 1994 Assistant Professor, School of Engineering, Hokkaido University
1982 – 1983 Lecturer, School of Engineering, Hokkaido University
1982 Awarded PhD in electronics, The University of Tokyo
1977 Graduated from Faculty of Engineering, The University of Tokyo