Development of Fine Crystal-Dispersed Transparent Materials for Optical Devices

通过本研究，我们建立了制备具有强磁光效应的石榴石铁氧体微粒和制备用于光学应用的透明微粒薄膜的条件，并通过共沉淀和随后的热处理成功地制备了平均粒径为50 nm的Bi和Ce取代的铁石榴石微粒。颗粒的饱和磁化强度和法拉第旋转约0.6倍小于散装石榴石先前报道。穆斯堡尔谱分析表明，这可能是由于四面体位置上的铁的部分缺陷所致。通过在颗粒表面涂覆表面活性剂，并在分散过程中使用砂振器，得到了颗粒均匀分散的磁性油墨。由于TiO_2-SiO_2系统具有高的光学折射率和高的硬度，这两个特性分别是减少光散射和在颗粒处产生高的磁性所必需的，因此，我们首次获得了具有垂直于膜平面的磁化强度的透明颗粒膜，其中石榴石颗粒分散在粘结剂-基体中。

Through this study, we have established conditions for making fine particles of garnet ferrites with strong magneto-optical effect and for making transparent particulate films for optical applications in which the particles were dispersed into binder-matrix.Fine particles of Bi- and Ce-substituted iron garnet with average particle size as small as 50 nm were successfully prepared by coprecipitation and subsequent heat treatment. The particles had saturation magnetization and Faraday rotation about 0.6 times smaller than those of bulk garnet reported previously. Mossbauer spectroscopy revealed that this may be attributed to partial deficiencies of irons at tetrahedral sites.The magnetic inks in which the particles were homogeneously dispersed were obtained by not only coating the particle surfaces with a surfactant but also using sand-shaker on the dispersion process. The system of TiO_2-SiO_2 was found to be promising as a binder-matrix because it has high optical index and high stiffness which are required for reducing optical scattering and inducing high magnetic coercivity at the particles, respectively.Thus, we have, for the first time, obtained transparent particulate films having magnetization perpendicular to the film plane in which the garnet particles were dispersed into the binder-matrix.