| 摘要 |
PURPOSE:To obtain a Tl-base oxide superconductor having a high critical temp. by using a raw material with the Ca content increased as compared a stoichiometry value of the composition expressed by Tl2Ba2CaCu2Oy and sintering the raw material in an oxygen-contg. atmosphere 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 Ca content is increased and the Tl content decreased as compared with a stoichiometry value of the composition expressed by Tl2Ba2CaCu2Oy ((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-u):2:(1+v):2 (where 0>=u<0.5 and 0.1<v<0.4). The starting material is sintered at 890-910 deg.C for 5-10min in an oxygen-contg. atmosphere. An oxide superconductor having a crystal structure expressed by Tl2Ba2CaCu2Oy is synthesized in this way as a single phase. |
