| 摘要 |
PURPOSE:To produce a large-sized ferrite single crystal, economically, in high yield, by contacting a single crystal ferrite to a surface of a polycrystalline ferrite, and heating the product while applying a means to suppress the discontinuous grain growth at the back surface of the polycrystalline ferrite. CONSTITUTION:A polycrystalline ferrite 2 prepared from iron oxide having spinel structure or having the history of spinel structure, and a single crystal ferrite 1 having the same composition as above, are polished to mirror surface. The polished faces are made to contact with each other interposing an organic acid or an inorganic acid therebetween, and a means 3 to suppress the discontinuous grain growth is applied to at least the back surface of the polycrystalline ferrite 2. The assembly is heated at about 1,300-1,350 deg.C. The crystal of the single crystal ferrite 1 is grown toward the polycrystalline ferrite 2, and the growth of the crystal having undesirable crystal direction can be suppressed by this process to obtain a large-sized ferrite single crystal 4. The above means to suppress the discontinuous grain growth is e.g. a dummy core of ferrite having low rate of crystal growth or a skin membrane formed by heating the polycrystalline ferrite. |
