高价离子掺入Bi(Pb)-Sr-Ca-Cu-O体系对成相和结构的影响

EFFECTS OF HIGH VALENCE CATIONS DOPED ON THE PHASE FORMATION AND THE CRYSTAL STRUCTURE IN THE Bi(Pb)-Sr-Ca-Cu-O SYSTEM

Sunshine等在Bi-Sr-Ca-Cu-O体系中掺入少量Pb^(2+)后,可获得T_(c(0))=110K以“2223”相为主的样品.其后,Shun-ichi、卢伟京等也得到同样的结果,但都需要长达300～500小时烧结,所得到的样品仍含有少量“2212”相、我们拟对Bi(Pb)-Sr-Ca-Cu-O体系掺入高价离子,M^(n+)(n≥4),如Sn^(4+),Sb^(5+),Mo^(6+),W^(6+),研究它们对“2223”成相和结构的影响。

The effects of high valence cations M^(n+) (n≥4) doped on the phase formation andthe structure stability have been investigated. In the crystal structure X_2Sr_2Ca_2Cu_3O_(10)(X = Bi_(1-x-y)Pb_xM_y), the high valence cations M^(n+), Bi^(3+), and Pb^(2+) were deter-mined to statistically distribute at the bismuth positions. The bismuth valence is raisedand the positions of oxygen atoms in the (XO_2X) double layers are fully occupied.Conseqently, The structural stability is increased. The phase 2223 was found to formmore rapidly by doping and the single phase with T_c(0)>110K can be obtainedmore easily.