TRIAL OF INTERCALATION OF BR AND LI INTO BI2SR2CAN-1CUNO2N+4 (N = 1, 2, 3)

Intercalation of Br and Li into Bi2Sr2Ca(n-1)Cu(n)O(2n + 4) (n = 1, 2, 3) has been tried. For heavily Br-intercalated samples of n = 2 and 3 with x almost-equal-to 1 in Bi2Sr2Ca(n-1)Cu(n)O(2n + 4)Br(x), enlargement of the c-axis is detected, suggesting that intercalation compounds Bi2Sr2Ca(n-1)Cu(n)O(2n + 4)Br with Br atoms between double BiO layers are synthesized. For Li-intercalated samples, on the other hand, clear evidence to show the formation of intercalation compounds is not obtained. For lightly Br- and Li- intercalated samples of n = 1, 2, 3, changes of the electrical resistivity, the Hall coefficient and T(c) by the intercalation are observed, which are attributable to charge transfer between intercalants and CuO2 planes in the host materials Bi2Sr2Ca(n-1)Cu(n)O(2n + 4). That is, the intercalation of Br and Li is effective for hole and electron doping into CuO2 planes, respectively. For n = 3, T(c) decreases by the light intercalation of both Br and Li, suggesting that Bi2Sr2Ca2Cu3O10 has almost optimum hole concentration to attain the maximum of T(c).