Super-spin glass with hierarchical structure aimed for a brain-type memory

点击翻译按钮获取中文摘要

Fundamentals of magnetism have been clarified for super-spin glass with hierarchical structure and amorphous oxide magnets which are prototype of random magnetic systems. For the former, an assemblage state of mesoporous silica microparticles with maghemite nanocrystals precipitated in the mesopores has been fabricated. The Faraday effect measurements reveal that the material show superparamagnetism at room temperature. As for the amorphous oxide magnets, oxide glasses containing both iron and rare-earth elements exhibit spin glass or super-spin glass transition, while amorphous EuZrO_3thin film shows re-entrant spin glass transition accompanied by ferromagnetic transition. The mechanism of these magnetic phase transitions have been elucidated.