For realizing perpendicular magnetic recording media (PRM) for hard disk drive (HDD), precisely controlled fabrication technology with angstrom scale according to the required properties is essential from material, processes, and physical view point. PRM presently consist of three functional parts; a soft magnetic underlayer (SUL), a nonmagnetic intermediate layer, and a recording layer (RL). The control of domain structure through interlayer coupling induced by RKKY-like interaction in SUL and narrower size distribution of the magnetic particles with magnetically decoupling in recording layer are indispensable for advanced PRM with high signal to noise ratio and thermal stability. In this paper, structure and magnetic properties for SUL and RL in a real fabricated PRM is discussed in connection with sputtering process parameters and also target materials.

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  Crystallographic orientation of the MgO barrier in sputter-deposited CoFeB/MgO/CoFeB magnetic tunnel junctions (MTJs) and its effect on tunnel magnetoresistance (TMR) were investigated. The degree of MgO(001) orientation was estimated with the integral intensity ratio (I₍₂₀₀₎/I₍₂₂₀₎) of diffraction lines from MgO(200) and MgO(220) planes obtained in grazing incident x-ray diffraction profiles. The main results are stated as follows. (1) I₍₂₀₀₎/I₍₂₂₀₎~4, meaning the (001) orientation of MgO, is realized when the underlaid CoFeB maintains amorphous structure, meanwhile MgO on bcc(110)-oriented CoFe shows (111) orientation (I₍₂₀₀₎/I₍₂₂₀₎=0). (2) The prevention of epitaxial growth on hcp(00.1)-oriented Ru layer is effective to maintain amorphous structure of CoFeB. (3) The achievable TMR ratio after high temperature (280°C-450°C) annealing is mainly dominated by the MgO orientation and giant TMR ratio exceeding 200% is only obtained with I₍₂₀₀₎/I₍₂₂₀₎≥3.4, while the resistance area product is independent of I₍₂₀₀₎/I₍₂₂₀₎.

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  Recently, research field of organic molecular spintronics has attracted much attention. One of important issues in this field is to clarify mechanisms of spin injection from ferromagnetic materials into organic molecules. The flatter interface between an organic molecular layer and a ferromagnetic electrode as a spin injector is, the more efficiently spin-polarized carriers are injected. In our study, a planer-type structure that had the flatter interface was adopted. By using electron beam lithography, photolithography and vacuum vapor deposition, Ni₈₀Fe₂₀/tris-(hydroxyquinolinato)-aluminum(Alq₃)/Ni₈₀Fe₂₀ junctions were fabricated and the magnetoresistance (MR) effect was investigated. Devices having shorter distance between Ni₈₀Fe₂₀ electrodes showed the MR effect. Origins of the MR were investigated by the devices with nonmagnetic electrodes, by the devices with tunnel barriers at the interface between the Alq₃ and the Ni₈₀Fe₂₀, and by the devices with another molecule. As the result, it was suggested that the MR was mainly originated from a local magnetic state on the Ni₈₀Fe₂₀ surface.

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  We have developed a reactive ion etching (RIE) technique for high-performance and damage-free magnetic tunneling junction devices (MTJ) using pulse-time-modulated (TM) plasma. Exposing MTJ devices to the conventional continuous-wave (CW) plasma widely used in plasma etching significantly degrades their magnetic characteristics. We found that it was caused by damaging the structure of the CoFe pinned layer. Conversely, exposure to a TM plasma does not degrades the MTJ devices' characteristics. Therefore, manufacturing processes that incorporate TM plasmas hold promise as device fabrication processes for MRAM and other magnetic devices.

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  An overview on the recent progresses in transparent conducting oxide thin films of In₂O₃, ZnO and TiO₂ concludes with a proposal that encourages the re-examination of the action and reaction of dopants with the host lattice in order to establish the deposition conditions that suppress the formation of undesirable defects in terms of carrier generation and mobility enhancement.

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  We report recent progress on sputter-deposition of Ti_0.94Nb_0.06O₂ polycrystalline (poly-TNO) thin films as ITO-alternative transparent conductor. In order to achieve low resistivity (ρ) in TNO, it is necessary to introduce oxygen deficiencies into anatase phase. However, growth of poly-TNO films on glass under relatively reducing atmosphere tends to stabilize the rutile phase with higher resistivity. We overcame this difficulty by developing a bi-layer technique using a TNO seed-layer, which prevents the formation of the rutile phase even under reducing deposition conditions. As a result, we succeeded in directly fabricating poly-TNO films with ρ of ~1×10^-3 Ω cm and visible transmittance of 60~80%, although we still need to further improve these properties towards practical applications. By comparing carrier transport properties between poly-TNO films obtained by different synthesis routes, we discuss on material parameters that govern resistivity of poly-TNO films.

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  A new kind of energy efficient window using switchable mirror thin film which can be switched between mirror and transparent state freely is developed. Pd capped Mg₆Ni thin film prepared by magnetron sputtering shows excellent switching property. By exposure to 4% H₂ in Ar, the metallic film turns to a transparent state within a few seconds dramatically. A large size switchable mirror glass is fabricated and its switching is confirmed. Also all-solid-state swithchable mirror device based on Mg-Ni alloy is developed. It can be switched by applying voltage of 5 V to the device. If the switchalbe mirror window will be used practically, it is effective to reduce energy consumption for air-conditioning in buildings and automobiles.

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  Rutherford backscattering spectroscopy (RBS) is one of the widely used surface analysis techniques for the measurement of composition depth profiles. It allows quantitative and non-destructive analysis with a depth resolution of ~10 nm. Using He ions of several hundred keV as a probe beam and a magnetic spectrometer for the energy analysis of scattered ions, the depth resolution can be improved to sub-nm region in RBS. This technique, called high-resolution RBS (HRBS), is an excellent technique for the analysis of ultra-thin films as well as surface and interface structures. After a brief description of the fundamentals of HRBS, some examples of the application of HRBS are presented, which includes analysis of high-k gate stack structures, the surface structure of an ionic liquid, trimethylpropylammonium bis(trifluoromethanesulfonyl)imide, and the combination analysis of HRBS and angle-resolved X-ray photoelectron spectroscopy.

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  To understand the mechanism of hydrogen release from materials used in vacuum technology, the release behavior of tritium from stainless steel SUS316 previously loaded with this gas was investigated isothermally at 423 K either under a stream of argon or under vacuum conditions. Depth profiles of the heated specimens were determined by chemical etching. The experimental release rate and the tritium depth profile in the solid could be simulated with a model based on bulk diffusion. The diffusion coefficients used to fit the depth profiles of specimens heated under vacuum at 423 K were non-discernible from those obtained with specimens heated under a stream of Ar at the same temperature.

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