Kenji Tanase

Magnetic expansion read-out of MSR disk with double in-plane magnetic layers

Magnetically induced super resolution (MSR) is a useful technique for high density magneto-optical storage. The magnetic domain expansion disk with double in-plane layers was prepared and its magnetic domain expansion read-out characteristics were measured. The film mainly consists of GdFeCo read-out layer, GdFeCo intermediate layer and TbFeCo memory layer. Given a difference in content of the GdFeCo readout and intermediate layers, it is clearly observed that there exists a threshold read-out laser power. When 0.6 /spl mu/m continuous domains were recorded on the magnetic expansion disk, the read-out signal level became about 2 times higher than that of a conventional CAD (Center Aperture Detection) disk without an external magnetic field.

High density recording on magnetically induced super resolution disk with magnetic field modulation and pulsed laser irradiation

The magnetically induced super resolution disk with an in-plane magnetized layer (CAD-MSR) is one of the most useful candidates for high density recording because of its simple structure and no initializing fields. This paper describes an evaluation of a CAD-MSR disk using magnetic field modulation with a pulsed laser, which is also useful for high density recording. We obtained a jitter of less than 10% at a bit density of 0.3 /spl mu/m/bit (2 T=0.4 /spl mu/m in (1,7) RLL code). The real density corresponds to an unformatted capacity of more than 5 Gbytes on a /spl phi/ 120 mm disk.

Microstructures of Pt/Co Films Deposited on Sputter-Etched Underlayers

Pt/Co multilayered films deposited on a sputter-etched SiN underlayer show larger magnetic anisotropy (1×106 erg/cm3) and better squareness(=1) than those on nonetched underlayers. The results of small-angle X-ray diffraction indicate the improvement of the multilayer structural order due to the etching. According to the transmission electron microscopy observation and the electrical resistivity measurement, the etching of underlayers transforms the Pt/Co films from island structure to continuous structure in an early stage of film growth. The scanning tunneling microscopy observation suggests that the sputter etching flattens the surface of the underlayer.

Magnetic properties of multilayered GdDyFeCo thin films

The variation in the magnetic properties of compositionally modulated GdDyFeCo films prepared by two-source magnetron sputtering as a function of the compositional period was investigated. The compositional period was varied by altering the substrate rotation rate; the minimum period was 1.5 AA. Variation of the compositional period caused great changes in the magnetic and magnetooptical properties, while films with a compositional period of 3 AA showed the optimum recording characteristics. Increasing the compositional period caused magnetization of the FeCo layers to increase, and the perpendicular magnetic anisotropy to decrease. The degradation in recording characteristics at 1.5 AA can be mainly attributed to the increasing demagnetization of the field between T/sub comp/ and T/sub c/ brought about by a change in the temperature dependence of saturation magnetization. >

44.2: Novel Front‐light System Using Fine‐pitch Patterned OLED

We have developed a novel front-light system that uses an organic light emitting diode (OLED) light source patterned with a fine pitch. The front-light system has the following characteristics: 1. Excellent uniformity within the light emitting area; 2. Emittance that is consistent at all viewing angles; 3. No light leakage at any viewing angle from the side of the observer. This system can be adopted for reflective LCDs, electrophoretic displays (EPD), microelectromechanical systems (MEMS) and other applications.

Thickness dependence of magnetic properties in GdDy/FeCo film

For a better understanding of the dynamic characteristics of GdDy/FeCo magnetooptical (MO) disks, the magnetic properties of GdDy/FeCo films with various thicknesses were investigated. The MO layer, whose thickness was varied from 200 AA to 1500 AA, was sandwiched by dielectric SiN layers. Kerr rotation angle decreased as the MO layer was made thinner, while the reflectivity showed little change. T/sub comp/ shifted lower with decreasing thickness, while T/sub c/ was constant. The CNR value saturated above 600 AA thickness, while noise level was less influenced with the thickness. Therefore, the increase in CNR is mainly due to the carrier level and caused by an increase of Kerr rotation angle. The degradation of CNR at lower magnetic fields is also discussed. >

Thermal stability of sputtered GdDyFeCo films with trilayer structure

The thermal stability of GdDyFeCo films with trilayer structure has been studied by annealing in vacuum up to 300/spl deg/C. In GdDyFeCo films sputtered on glass, the coercivity is reduced after annealing, which is thought to be due to a structural relegation caused by annealing. The saturation magnetization tends to increase upon annealing, in particular for rare-earth rich composition because of the increase of effective magnetic moment, making the compensation temperature (Tcomp) shift higher. The films with Tcomp between room temperature and 100/spl deg/C show superior thermal stability, because their magnetic properties, especially Tcomp, change little after annealing. Overwrite repetition tests using magnetic field modulation recording also indicate that the disks with the Tcomp between room temperature and 100/spl deg/C have superior overwrite durability. Small adjustments of the GdDy content seem to be effective in improving the thermal stability of GdDyFeCo films. The best Tcomp of the GdDyFeCo films is between room temperature and 100/spl deg/C, and the optimum Dy:Gd ratio is between 45/55 and 70/30. >

31.5L: Late-News Paper: Development of a Combined Liquid Crystal and Fine Pitch Light Source Display (LFD)

We propose a novel display system that we call an LFD (combined liquid crystal and fine pitch light source display). In an LFD, an auxiliary light source patterned with a fine pitch is attached to a reflective liquid crystal display (LCD), and a light shield is formed on the observers side of the light source. A vertical alignment LCD (VA-LCD) is attached as the reflective LCD, and an organic light-emitting diode (OLED) is attached as the fine pitch light source. An LFD can produce bright, high-contrast images under any ambient light. We built a test sample and confirmed its display characteristics.

Life estimation based on statistics for single-sided Magneto-Optical disks with GdDyFeCo film

We have developed single-sided Magneto-Optical (MO) disks with GdDyFeCo film, which is suitable for magnetic field modulation method at low constant velocities. The reliability of our MO disk with a simple structure (polycarbonate/ SiN/ GdDyFeCo/ SiN/ UV resin) was examined with accelerated tests. After aging more than 10,000 hours at 65°C 85% RH, carrier to noise ratio was scarcely lowered, while the value of Block Error Rate increased because of extra noise which was produced by local defects. From the statistical analysis and Arrhenius plot, the lifetime of 95% of our MO disks were estimated to be more than 50 years at an office environment.