The prospect of lattice structure and ferroelectricity of SnTiO3 have been studied by first-principles calculations within local density approximation. The results showed that the SnTiO3 has the minimum total energy within almost tetragonal perovskite structure of a=b=3.80 Å, c=4.09 Å. The calculated electronic structure of SnTiO3 resembles that of PbTiO3 because the Ti 3d states, Sn 5s and 5p states hybridize with the O 2p orbitals. The moment of spontaneous polarization of SnTiO3 was estimated as 73 μ C/cm2, which is as large as that of PbTiO3.

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We have studied the effects of hydrogen concentration and hydrogen configuration on the light-induced change, called Staebler-Wronski effect, in a-Si:H. A strong correlation is found between the light-induced spin density and the fractional hydrogen content evolved at low annealing temperature. The light-induced defects are supposed to be created through the breaking of weak Si-Si bonds in the regions containing clustered SiH or SiH2 bonds.

A CoPtCr-SiO2 film is a potential material for high-density perpendicular recording media due to their high magnetic anisotropy constant Ku. However, the value of Ku decreases in high levels of Pt content. In this study, this phenomenon was analyzed by synchrotron radiation grazing incidence x-ray diffraction and transmission electron microscopy techniques. Although the CoPtCr-SiO2 films contained almost no fcc phase at 20at.% Pt or less, it increased remarkably at 30at.% Pt. This result coincided with the variations of Ku with respect to the Pt content for the CoPtCr-SiO2 films. We consider that the fcc phase formation at Pt content levels in the vicinity of 30at.% is an influential factor of the Ku reduction. Our techniques proved to be sensitive for the detection of fcc regions in the CoPtCr-SiO2 films.

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