In this paper, Barium ferrite thin films were prepared by Facing Targets of Sputtering (FTS) and annealed at various temperature, and the effects of the substrate temperature during deposition on the structural and the magnetic properties of the films were discussed. The films were crystallized by annealing and their crystal structures depend on the substrate temperature. Furthermore, after annealing at 800℃, the film which was deposited at room temperature is about 3kOe of the coercivity as same as the film which deposited at 500℃. The coercivity or the film deposited at 300℃ is less than 1.5kOe. It was clear that the structural and magnetic properties of the films after annealing were affected by the substrate temperature during deposition and the film deposited at room temperature is expected to get more excellent magnetic properties for the high density magnetic recording media.

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Reduction of crystallite size in BaM thin film magnetic recording media was investigated. The crystallite size of BaM thin film deposited on thermally oxidized silicon wafer substrate decreased monotonically as the film thickness decreased and took a value less than 30nm in the film with a thickness below 20nm. However, coercivity of the film decreased significantly as the film thickness decreased below 30nm. This reduction was seemed to be caused by an increase in the amount of particles with super para magnetism. Control of crystallite size of the BaM thin film was attempted by controlling the crystallite size of ZnO underlayer. The ZnO underlayer promoted the growth of hexagonal BaM crystallites on it, but the reduction of the crystallite size in the underlayer was not effective to reduce the crystallite size of the BaM thin film.

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We Studied the degradation mechanism of magnetic properties of obliquely evaporeted Co-O film caused by residual gas. It was found that the coercivity (Hc) and squareness ratio (Mr/Ms) decreased with increasing water vapor in residual gas. Higher the water vapor pressure, the more increased easy axis angle from the film plane, and decreased anisotropy field. This suggests the Co vapor scattering by water molecule. In addition, the higher water vapor pressure leads to less oxidation of evaporated Co-O film due to oxygen gas. It is suggested that the strong, sticking probability of water molecule to deposition film surface prevents Co film from oxidation.

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Small magnetic domains with 0.15μm in diameter were recorded on magnetic recording media using a Magnetic Force Microscope (MFM) probe. The probe was a SiN tip coated with a PtCo thin layer by sputtering method. The recording medium was a sputter-deposited chromium thin film with oxidized layer on its surface. We have obtained a relation between the magnetic properties of the probe and that of the recording media for ultra-high-density recording.

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Scanning near-field optical microscope (SNOM) with a resolution beyond the diffraction limit was applied to phase-change recording. Pulsed laser light was incident through the SNOM probe onto the as-deposited amorphous GeSbTe film, which can heat the sample locally and change the phase of the region into the crystalline state. It was found that the minimum size of the marks was 〜80nm, which can achieve the recording density of 〜100 Gb/in2 with the closest bit writing. The model calculation shows that the writing mechanism with SNOM is dominated by the heat transfer from the probe.

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We have investigated the dependence of magnetic and magneto-optical properties on TM layer thickness and bilayer period for NdGd/FeCo MLs, which are one of candidates for MO media using a short wavelength laser. The NdGd/FeCo disk together with TbFeCo disk for comparison were prepared by rf magnetron sputtering on glass substrate. We have measured writing and reading characteristics for those disks by magnetic modulation method using Ar gas laser (wavelength : 458 nm). We have found that the CNR of NdGd/FeCo disk is 3 or 4 dB higher than that of TbFeCo, which is considered to be due to a larger magneto-optical figure of merit √R・θ_K of NdGd/FeCo. It was also confirmed that small bits of 0.4 μm are recorded on NdGd/FeCo disk.

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Ar sputtered Co/Pt multilayers are prepared to study the Ar gas pressure and film thickness dependence of magnetic and magneto-optical properties. The 20mTorr-samples have large coercivity, H_C, but Kerr rotation angle, θ_K, and reflectivity are not sufficient for application. The 10m Torr-samples with 3〜5Å Co layer thickness and 10Å Pt layer thickness are the best candidates. Addition of Nd or Pr to Co layer does not enhance H_C nor θ_K. However, θ_K for the light wave length of 〜400nm normalized by the data at 780nm increases with Nd or Pr concentration. It suggests that the enhancement of θ_K is possible if we can compensate the decrease of magnetic moment.

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We have investigated magnetization and magnetostriction properties of amorphous alloy films of the ternary system Tb_<40-x>Ho_xFe_<60> prepared by rf-magnetron sputtering to develop thin film actuator materials. For this purpose, the materials must equip soft magnetism retaining large magnetostriction to enable small magnetic field drive. It is found that films having magnetic softness (coercivity Hc&cong;20Oe) and a considerably large saturation magnetostriction constant λs exceeding 100×10^<-6> can be realized at the composition around x=15at.%.

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Previously we reported that films with the ternary oxide system of Bi_2O_3-Fe_2O_3-ABO_3 (ABO_3 : BaTiO_3,PbTiO_3,PbZrO_3 etc.) prepared by rf-reactive sputtering exhibit distinct magnetic as well as dielectric hysteresis loops simultaneously above room temperature only when the films have Fe_2O_3 concentration around 70% after subject to thermal annealing around 700℃. In this study, we have prepared the same oxide system films by sol-gel method, where PbTiO_3 was chosen for ABO_3. It is found that gel-coated films onto glass plates and/or Si-wafers also possesses similar properties to those rf-sputtered films. Microstructure of the films was examined by EXAFS. It may be concluded that the amorphous state is essential for realizing these properties, presumably caused by strong frustration in glassy antiferromagnet.

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Magnetically induced super resolution disk with in-plane magnetized layer (CAD-MSR) is one of the most useful candidates for high density recording media because of simple structure and no initializing fields. In this paper, we evaluated a CAD-MSR disk using method of magnetic field modulation with pulsed laser, which is useful for high density recording and land/groove (L/G) recording. We can get a jitter of less than 10% at a bit density of 0.3 μm/bit (2T=0.4 μm in (1,7) RLL code). The real density corresponds to unformat capacity of 5 Gbytes with φ120 mm disk.

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