| 摘要 |
PURPOSE:To obtain a Tl-base oxide superconductor having a high critical temp. by using a raw material with the Tl content decreased and the Ca content increased as compared with Tl2Ba2Ca2Cu3Oy and sintering the raw material in the presence of oxygen with the temp. and time controlled. CONSTITUTION:Tl2O3, BaCO3, CaO, CuO, etc., as the raw materials are mixed to prepare a starting material, in which the Tl content is decreased and the Ca content increased as compared with a stoichiometry value of the composition expressed by Tl2Ba2Ca2Cu3Oy ((y) is the number meeting the requirement of valence). The mixing ratio of the raw materials in the number of atoms of Tl, Ba, Ca and Cu is appropriately controlled to (2-alpha):2:(2+beta):3 (where 0.1<alpha<0.6 and 0.1<beta<0.5). The starting material is sintered at 890-910 deg.C for 5-10min in an oxygen-contg. atmosphere and then cooled at a rate of >=10 deg.C/min. An oxide superconductor having a crystal structure expressed by Tl2Ba2Ca2Cu3 Oy is synthesized in this way as a single phase. |
