Optically Transparent Ferromagnetic Nanogranular Films with Tunable Transmittance.
Developing optically transparent magnets at room temperature is an important challenge. They would bring many innovations to various industries, not only for electronic and magnetic devices but also for optical applications. Here we introduce FeCo-(Al-fluoride) nanogranular films exhibiting ferromagnetic properties with high optical transparency in the visible light region. These films have a nanocomposite structure, in which nanometer-sized FeCo ferromagnetic granules are dispersed in an Al-fluoride crystallized matrix. The optical transmittance of these films is controlled by changing the magnetization. This is a new type of magneto-optical effect and is explained by spin-dependent charge oscillation between ferromagnetic granules due to quantum-mechanical tunneling.
Research Institute for Electromagnetic Materials, 2-1-1, Yagiyama-minami, Taikaku-ku, Sendai 982-0807, Japan.
Nobukiyo
N
Kobayashi
Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3, Aramaki aza Aoba, Aoba-ku, Sendai 980-8578, Japan.
Hiroshi
H
Masumoto
Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
Saburo
S
Takahashi
Advanced Science Research Center, Japan Atomic Energy Agency, 2-4, Shirakata Shirane, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195, Japan.
Sadamichi
S
Maekawa
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