|Budget Amount *help
¥2,200,000 (Direct Cost : ¥2,200,000)
Fiscal Year 1997 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1996 : ¥1,400,000 (Direct Cost : ¥1,400,000)
La0.3mol%doped BaxSr1-xTiO_3 single crystal was grown by Floating zone method (Xe arcimage and Harogen ramp). The single crystal of which x value were 0,0.05,0.10 could be grown by using of Floating zone method. This condition of growth was noted. The growth rate (feeding speed) was 1.7cm/hr, and its atmosphere was air which flow rate was 0.51/min. The sizes of single crystal was almost 3mm phi and the color was dark blue. So at first, wecan find out that this crystal was reduced strongly. The value of x except this range colud not be grown by this same method. In this range, grown crystal had light blue color and the surface condition was dull. This growth direction was (001), (210), (111) respectively.
Microstructure and electrical properties of La-doped semiconductive SrTiO_3 bicrystals were investigated. SrTiO_3 bicrystals having several kinds of twisted angle were prepared by hot pressing at 1662oC,0.1MPa for 5h in air. Angular shaped boundary layrs were observed between the crystals. Many closed pores were observed at the center of boundary layrs, and open pores were observed at the edge of boundary layrs. Non-linear I-V characteristics across the junction of the bicrystals were measured on as prepared samples. The non-linear coefficient of the sample was relatively larger than that of a simple junction without boundary layrs. The I-V characteristics of bicrystals could be changed from non-linear to linear by heating the sample in an H_2-N_2 mixed gas atmosphere. Furthermore, by heating in an O_2 atmosphere the linear I-V characteristics of the samples reversed to non-linear.