Kiyozumi Niizuma

The saturation magnetization of FeN films prepared by nitriding treatment in N2 plasma

Abstract The saturation magnetization M s of polycrystalline iron thin films increased by approximately 10% after the films were treated by ion nitriding for about 1 h. In the nitride treatment, we used the magnetron discharge method to increase the energy density of the discharge. The rate of increase in M s was 21.2% after the iron thin film was nitrided under an N 2 gas pressure of 4.5 × 10 −2 Torr. Fe 16 N 2 , γ′-Fe 4 N, ϵ-Fe 3 N, ζ-Fe 2 N and α-Fe phases were detected by the X-ray diffraction method in nitrided thin films under various N 2 gas pressures. The saturation magnetization M s of Fe 16 N 2 , calculated by using X-ray integrated intensity ratios, was 2210 e.m.u. cm −3 in the nitrided thin film under an N 2 gas pressure of 4.5 × 10 −2 Torr, and the M s of Fe 16 N 2 , calculated by using X-ray integrated intensity ratios, was 1710 e.m.u. cm −3 in the nitrided thin film under an N 2 gas pressure of 7.5 × 10 −2 Torr.

Magnetic Properties of Iron Nitride Thin Films Prepared by the Magnetron Discharge Method

The saturation magnetization M<inf>s</inf> of polycrystalline iron thin films increased by approximately 10% after films were subjected to ion nitriding treatment for about one hour. In the latter treatment, the magnetron discharge method was used to increase the energy density of the discharge. The rate of increase of M<inf>s</inf> was 21.2% after the iron thin film was nitrided under an N<inf>2</inf> gas pressure of 4.5×10^¿2 Torr. X-ray diffraction studies revealed the presence of Fe<inf>16</inf>N<inf>2</inf>, ¿¿-Fe<inf>4</inf>N, ¿-Fe<inf>3</inf>N, ¿-Fe<inf>2</inf>N, and ¿-Fe phases in thin films nitrided under various N<inf>2</inf> gas pressures. The saturation magnetization M<inf>s</inf> of Fe<inf>16</inf>N<inf>2</inf>, calculated using X-ray integrated intensity ratios, was 2210 emu/cc in nitrided thin films under an N<inf>2</inf> gas pressure of 4.5×10^¿2 Torr, and the M<inf>s</inf> of Fe<inf>16</inf>N<inf>2</inf>, calculated using X-ray integrated intensity ratios, was 1710 emu/cc for thin film nitrided under an N<inf>2</inf> gas pressure of 7.5×10^¿2 Torr.

Synthesis of Fe–N gradient foil by nitrogen plasma

Abstract We investigated the effect of treatment temperature on the magnetic property of Fe–N gradient foils irradiated with nitrogen plasma. Fe–N gradient foils irradiated with nitrogen plasma were composed of e -Fe 2-3 N, γ′-Fe 4 N and γ nitrogen austenite in α-Fe matrix. The outermost region of Fe–N foils was composed of various iron nitrides, and the inner region was composed of α-Fe. The saturation magnetization σ s of Fe–N foils decreased with increasing the surface temperature. The coercive force H c of Fe–N foils increased with increasing the surface temperature. The value of σ s estimated by Mossbauer parameters agreed with the σ s measured by VSM.

Soft Magnetic Properties of Super Sendust/Fe Multilayer Thin Films Prepared by the IBS Method

The magnetic alloy Super Sendust (SS(I)) has a high saturation magnetization and high permeability. This paper reports on the magnetic properties of SS(I)/Fe multilayer thin films prepared by the ion beam shuttering method. As-deposited SS(I)(130Å)/Fe(130Å) multilayer thin films have a saturation magnetization of 1350 emu/cc, a coercive force of 2.2 Oe, and an effective permeability of 700. Multilayer thin film annealed at 350°C in vacuum for one hour exhibits a low coercive force of 0.5 Oe and a high effective permeability of 1250. Based on experimental results in which the soft magnetic properties were improved by heat treatment, it seems that internal stress relaxation is caused by a decrease in the interplanar spacing.

Electrical Property of TiO2 Thin Film Deposited by RF Sputtering

The authors investigated on the electrical property and the photo-catalytic activity of TiO2 thin films deposited in Ar+O2 atmosphere by RF magnetron sputtering. From the result of x-ray diffraction, the anatase phase was formed in TiO2 thin films. In TiO2 thin film deposited under a gas pressure of 3.0Pa, the contact angle of water showed 9 ﾟ, and the decomposition rate of Methylene Blue (measuring the absorbance of the reference light) showed -0.067 with UV light irradiation. Moreover, it revealed that the electric resistivity of TiO2 thin film deposited under the same conditions decreased from 8.0×103Ω･m to 1.4×10-2Ω･m with UV light irradiation.