Superconductivity in the halogen-intercalated Bi₂Sr₂(Gd_0.82Ce_0.18) ₂Cu₂O_10+δ of the Bi-2222 phase

The effects of halogen (I₂, Br₂, IBr) intercalation on the electrical resistivity, thermoelectric power and superconductivity have been investigated in the non-superconducting Bi₂Sr₂(Gd_0.82Ce_0.18) ₂Cu₂O_10+δ of the Bi-2222 phase. It has been found that as-sintered samples of the Bi-2222 phase are non-superconducting for lack of carriers in the CuO₂ sheets and that the IBr intercalation is very effective for the carrier doping into the CuO₂ sheets and gives rise to superconductivity of the bulk at low temperatures below about 20 K. There is a possibility that T_c of the Bi-2222 phase will increase through further carrier-doping, because the superconducting samples are still located in the underdoped regime.