高掺杂Sn对Y-Ba-Cu-O体系结构和性质的影响

通过对高掺杂Sn的YBa₂Cu_3-xSn_xO_7-y体系的穆斯堡尔谱测量,确定了掺杂的Sn全部以Sn⁴⁺离子形式存在,多数占据Ba,Y,Cu(2),少量占据Cu(1)位置,Sn含量x不同,其在各个位置上的占有比例也不同,超导电性测量表明,该系列样品T_c大都在77K以上,Cu(2)和Y位上的金属离子被替代对超导温度T_c影响不大,为Cu-O面不是超导的主要原因关键词：

INFLUENCE OF HIGH Sn CONCENTRATIONS ON THE STRUCTURE AND PROPERTIES OF Y-Ba-Cu-O COMPOUNDS

Mossbauer measurements of YBa₂Cu_3-xSn_xO_7-y compounds with high Sn concentrations have revealed that the Sn dopants all exist as Sn⁴⁺, with their majority occupying Ba, Y, Cu(2) sites, and only a small part at Cu(l) sites. The amount of Sn at each site varies with Sn content (x). As for superconductivity, the sample systems are all with T_c above 77 K, this indicates that the substitutions for the metal ions on Cu(2) and Y sites have small effect on T_c, which strongly supports the concept that Cu-O plane does not predominate the superconductivity.