Norimoto Nouchi

Effective creation of oxygen vacancies as an electron carrier source in tin-doped indium oxide films by plasma sputtering

We have investigated the effect of hydrogen on the resistivity, Hall mobility, and carrier density of ITO films on glass substrates using a low-pressure plasma sputtering method. It was found that a certain hydrogen content in the Ar plasma leads to improvement in the resistivity relating to an increase in the electron carrier density. The improvement is explained by oxide reduction due to the reaction of hydrogen radicals with indium oxide (In2O3). The effect of postannealing on the electrical properties confirmed that the improvement of the resistivity is a result of an increase in oxygen vacancies as the electron carrier source in the ITO film. Oxygen extraction in the initial stages of ITO film growth, due to the glass substrate surface, is suggested to create oxygen vacancies as the electron carrier source for improvement in the resistivity of the films.

Magnetic properties of FeCoV film sandwiched by thin soft-magnetic films

Soft magnetization of FeCoV thin films has been examined experimentally. The coercive force of FeCoV films decreases by more than 90% with little reduction in saturation magnetization or changes in magnetization behavior when films are sandwiched between two thin FeNiMo soft-magnetic layers making up about 2% of the total volume. It can be assumed that a magnetic wall, parallel to the film surface and formed at the interface between the soft-magnetic layer and the FeCoV layer, will readily propagate into the FeCoV layer. The thickness of the soft-magnetic layer necessary for the magnetic wall formation is thought to be about 50/spl sim/100 /spl Aring/. The reduction in coercive force seems to be related to the anisotropy of the magnetic properties of the thin soft-magnetic layer. In the case of Fe films, however, a reduction in coercive force due to the thin soft-magnetic layer never occurs. Whether the thin soft-magnetic layer has effects on the crystal structure of FeCoV or Fe layers, will be examined experimentally in the future.

Coercive force reduction effect in FeCoV and FeNi films due to ultrathin FeNiMo layer

The mechanism of the drastic coercive force reduction effect in essentially semi-hard FeCoV and FeNi films due to ultrathin FeNiMo layer has been examined. It is noted experimentally that a kind of a coupling of magnetic moments existing between ultrathin FeNiMo layer with anisotropic magnetization and semi-hard magnetic layer with anisotropic magnetization contributes to this drastic coercive force reducing effect.