| 摘要 |
PURPOSE:To make a homogeneous solid solution of Nb2O5 or Ta2O5 in strontium titanate simultaneously with the growth of the strontium titanate single crystal by floating zone method, by specifying the composition of the raw material rod, and controlling the partial pressure of oxygen in the atmosphere during the crystal growth. CONSTITUTION:A single crystal is obtained by melting one end of the raw material rod, and shifting the formed molten zone thereby continuing the melting of the rod and deposition of the solid phase. In the above process, a strontium titanate single crystal is prepared by using a raw material rod composed of TiO2, SrO, and Nb2O5 or Ta2O5. The crystal growth is carried out in a reducing atmosphere having an oxygen partial pressure of <=10<-0.5> atm, thereby adjusting the valence of Nb2O5 or Ta2O5 in the raw material rod to a proper level and making a solid solution. The molar ratios of SrO: TiO2: (Nb2O5 or Ta2O5) in the raw material rod are about 1:(1-x):x (x is about 0.002-0.01), and when a solvent is used in the process, those of the solvent are about 1:(1-y):y (y is about 0.001-0.01). |
