ペーター・グリュンベルグ教授特別講義

Prof. Dr. Peter Grünberg Special lecture

金属材料研究所、国際高等研究教育機構、グローバルCOEプログラム「材料インテグレーション国際教育研究拠点」の共催により、 2007年ノーベル物理学賞受賞者で東北大学ユニバーシティプロフェッサー・名誉博士ペーター・グリュンベルグ教授の特別講義が2009年12月21日、青葉記念会館（東北大学青葉山キャンパス）で行われました。

講義に約60名が参加し、その多くが学生で、グリュンベルグ先生に活発な質問が出され、盛況をみせた講義になりました。講義内容の概略は次の通りです。

Spintronics and its applications

Due to the discovery of the Giant Magnetoresistance (GMR) effect in 1988, in subsequent years readable storage capacity of hard disk drives (HDD) could be increased by approximately a factor of 100. This remained not the only application in this new field, sometimes also called spintronics. In conjunction with a permanent magnet attached to a moving part it can be used to sense its position speed or rotation. This principle can be applied in macroscopic systems such as traffic as well as on the microand nano scale for the detection of biomolecules.

Progress in GMR soon also stimulated new efforts in tunnel magnetoresistance (TMR) with the result that TMR effects of the order of 500% have been observed (as compared to only 20% in equivalent GMR structures). They are now also used in HDDs and challenge GMR. In GMR magnetic alignment in these layered structures has an effect on electrical resistivity. There is also an inverse effect to this called “Current Induced Magnetic Switching” where spinpolarized currents have an impact on magnetic order.

The possibility of using this in magnetic data storage is obvious.