AUSTRALIA - JAPAN SYMPOSIUM
AUSTRALIA - JAPAN SYMPOSIUM ON EARTH SYSTEMS SCIENCE
AND ON NANOMATERIALS
Canberra, 21 November 2006
Materials design by computation for spin electronics
Professor Junjiro Kanamori, International Institute for Advanced Studies, Japan
Professor Junjiro Kanamori received his D.Sc. from Osaka University, in 1957. He was appointed a full professor
in 1965 in the Department of Physics, Osaka University until appointment as President of Osaka University
for the period 1991-1997. He has since then been a Professor Emeritus since then Director of the International
Institute for Advanced Studies since 2001.The Institute promotes interdisciplinary research in humanity, social
science and natural science on the problems concerning the future of humankind. His did theoretical research
mostly in the field of magnetism of solids and related statistical physics. He still has a close contact with
research groups of computational physics. He chairs the selection and evaluation subcommittee of the JSPS
21st Century COE program.
The usefulness of ab initio calculations of electronic structure of solids has been proved by several successful predictions of candidate materials for spin electronics. I will review some of such recent developments. A representative achievement is the spin-dependent tunneling conduction through Fe/MgO/Fe predicted by Butler et al in 2001 which opened a path to MRAM. I will then present the efforts being made recently by Japanese researchers to develop methods, elucidate the electronic structure of known materials and design new ferromagnetic substances and half-metallic materials; the half-metals are candidates for the source material of polarized spin current, being metallic in one spin direction and insulating in the other.
I first discuss ab initio calculations and also three principal mechanisms, double exchange, superexchange and s-p polarization underlying ferromagnetism and antiferromagnetism in solids in order to elucidate guiding principles of the design for magnetic materials. I report then on illustrative examples of computational materials design which include extensive investigations of double perovskites, III-V and II-VI magnetic semiconductors containing transition element ingredients and the designing an antiferromagnetic semi metal by doping semi-conductors with two kinds of transition elements.
