Tsuyoshi Maro

The effect of Ti underlayer on magnetic properties of Co-Cr thin films

The effect of a Ti underlayer on Co-Cr thin film was investigated from the crystallographic and morphological points of view. The Co-Cr film on a Ti underlayer has a larger perpendicular magnetic anisotropy and coercive force than that deposited directly on a polyimide film substrate. It is found that the improvement of perpendicular magnetic properties by the insertion of a Ti underlayer is not due to the improvement of the crystallographic c-axis orientation, but is due to the formation of a uniform columnar structure.

Study on the surface oxidation of Co-Cr films

The tribological properties of a Co-Cr thin film were greatly improved by surface oxidation. According to surface analyses, a Cr-rich oxidized region in which Cr is oxidized to Cr/sub 2/O/sub 3/ was formed near the surface of the film. This region plays an important role in improving the mechanical durability of the film. However, when the oxidation is carried out for a long time, a thick Co-rich oxidized region grows on the Cr-rich oxidized one. As a result, the durability deteriorates. >

Magnetic Properties and Microstructures of Fe-Polyethylene Co-Evaporated Films

The magnetic properties, the microstructures and the chemical binding state of carbon atoms of Fe-polyethylene films prepared by co-evaporating Fe and polyethylene were investigated. Magnetic property measurements revealed that the dependence of the saturation magnetization of Fe-polyethylene films on the carbon content was different from that of sputtered Fe–C films, and that Fe-polyethylene films with the carbon content of 11–13 at.% exhibited good soft magnetic properties. The magnetic properties of the Fe-polyethylene film with the carbon content of 11 at.% were as follows; Ms=1390 emu/cm3, Hc=2 Oe, µ=2000 (at 1 MHz), µ=900 (at 10 MHz). The temperature dependence of Ms and Hc indicated that the crystallization temperature was about 240–260°C. The results of XPS showed that most carbon atoms in the Fe-polyethylene films chemically combined with Fe atoms.

Influence of Self-Reorientation Effect on Isothermal and DC Demagnetization Remanence Curves

We have calculated two types of remanence curves (Ir: isothermal remanence curve and Id: DC demagnetization curve) using a phenomenological model based on the mean field theory and the normal distribution function as the switching field. In this paper, the reorientation effect of magnetic moments due to the internal field in the absence of the external field is taken into account. The model shows that this effect plays an influential role in Ir and Id curves for magnetic materials with large negative interaction coefficients.

Distinct Duplex Oxide Scale of Surface-Oxidized Co-Cr Film Observed by Auger Electron Spectroscopy

The structure of a surface-oxidized Co-Cr film for perpendicular magnetic recording media is investigated by Auger electron spectroscopy. It is found that an oxidized Co-Cr film has a distinct duplex oxide scale on its surface when oxidation is carried out at relatively high temperature (~400°C). From the outermost surface of the film, a CoO-dominant oxide scale and Cr2O3-dominant oxide scale are formed on the Co-Cr alloy film in order.

CoCr-polyethylene co-evaporated films

This is a report on CoCr-polythylene films synthesized by co-evaporation of CoCr and polyethylene. Through structural and magnetic analyses of CoCr-polyethylene co-evaporated films, it is found that by including amounts of polyethylene, CoCr films become amorphous and their magnetic properties change from hard to soft to superparamagnetic as the amount of polyethylene in the films increases. The results indicate that amorphous metallic alloys can be produced from combinations of metals and polymers as well as by the conventional methods.

Origin of perpendicular magnetic anisotropy of Ni‐polyethylene coevaporated films

The origin of the large perpendicular magnetic anisotropy (0.5–1×10−6 erg/cm3) of Ni‐polyethelene coevaporated films has been studied. It is indicated that the anisotropy can be very well explained by uniaxial anisotropy induced by the large tensile stress (1–3×1010 dyn/cm2) through the inverse magnetostrictive effect. Other factors, such as magnetocrystalline or shape anisotropy, produce little effect on the perpendicular anisotropy of the films.