Cr添加V_2O_3膜のゾル-ゲル法による作製とその抵抗率-温度特性

概要

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Films of Cr-added V_2O_3 were prepared by reduction of sol-gel-derived V_2O_5 films at temperatures over 500°C in flowing H_2. Auger electron spectroscopy of the films showed that atoms of V and O were distributed homogeneously on thickness direction. From X-ray photoelectron spectroscopy of the films, it was found that the reduction was enhanced with an increase of the reduction temperature, however, even at 900°C reduction valence of V still interposed between +3 and +4. The specific resistivity(ρ)-temperature(T)curves of the films showed antiferromagnetic insulator(AFI)-metall(M)transitions, but not metal(M)-insulator(I)transitions. Grain diameters of Cr-doped V_2O_3 powders prepared in the same way of the films increased by sintering at 1000 to 1350°C for 5 h in flowing mixture gas(95 vol%N_2+5vol%H_2). The M-I transitions was observed in the ρ-T curves of these powders heated at 1200°C and higher. Absence of M-I transition of sol-gel-derived V_2O_3 films was considered to be due to small grain sizes and/or small crystallite size of films.
社団法人日本セラミックス協会の論文
1999-04-01