電界効果トランジスタPb(Zr,Ti)O_3/(La,Ba)MnO_3を用いた金属絶縁体転移温度の室温制御(薄膜)

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We fabricated ferromagnetic La_<0.8>Ba_<0.2>MnO_3 thin films and systematically investigated the Curie temperature (T_c) for film thickness dependence. T_c was defined as a maximum peak of a dM/dT. We found that the T_c gradually increased with decreasing film thickness from T_c of the bulk (270 K). The 20-nm-thick film showed a maximum peak of T_c (= 310 K) against the thickness and a T_c decreased blow 20-nm-thick film. However, even the ultra thin film with 5 nm thickness had a T_c of 290 K, near room temperature. In order to apply this result to an application working at room temperature, we constructed field-effect transistor structures using the ferromagnetic (La, Ba)MnO_3 ultra thin film with the aim of controlling the metal-insulator transition at room temperature by applying an electric field. Investigations revealed that the transition temperature changed from 237.0 K to 242.0 K for the La_<0.90>Ba_<0.10>MnO_3 channel layer by ferroelectric remnant polarity (±50 μC/cm^2) and from 280.5 K to 283.0 K (±26 μC/cm^2) for the La_<0.85>Ba_<0.15>MnO_3 channel layer. These shifts, which were linearly proportional to the magnitude of ferroelectric remnant polarization, are induced by the accumulative charge due to the electric field.
社団法人日本磁気学会の論文
2004-03-01