スパッタ法によるＮｉ‐Ｏ膜の結晶構造と磁気特性

Abstract

Effects of O2 partial pressure at sputtering on the crystal structures and magnetic properties of Ni-O films werestudied. The film thicknesses were 150 nm for Ni and 500 nm for NiO. The following results were obtained. (1)Below 10% of O2 partial pressure [O2/(Ar+O2)], single-phase Ni films were obtained; above 10%, single-phase NiO films were obtained. (2)Lattice constants of both Ni and NiO were larger than those ofbulk Ni and NiO. (3)The saturation magnetization Ms is 90% that of the bulk. Anisotropy of magnetic susceptibility x was observed, andaverage value is the same as that of the bulk. (4)Coercive force(Hc)of the Ni film at O% is 1.1 kA/m at easy albs and O.9 kA/m at hard axis. (5)Electric resistivity ρ for Ni tends to increase with O2 partial pressure. The ρ of NiO which indicates semiconductor properties is only by four order larger than that of Ni, and is by four order smaller than thatof bulk NiO. It is thought that the NiO film composition is not stoichiometric, and the film is Ni-defect type (P-type) semiconductor.