Synthesis and properties of HgI 2 intercalation of Bi 2Sr 2CaCu 2O y superconductor

Abstract

Polycrystalline or single crystals of HgI 2 intercalated Bi 2Sr 2CaCu 2O y (Bi2212) have been synthesized and their properties have been studied together with those of HgBr 2 intercalates. Single crystals of HgI 2 intercalated Bi2212 were synthesized by a stepwise intercalation method using iodine intercalate as a secondary host material. These could not be obtained through direct intercalation methods by which polycrystalline sample were obtained. From ac susceptibility and resistivity measurements, superconducting onset temperature ( T con) for polycrystalline HgI 2 intercalate was found to be 82 K which was higher than that of the host (75 K). On the other hand, T con for single crystal HgI 2 intercalate was shown to be 79–80 K which is lower than that of host (95–97 K). The effect of HgI 2 or HgBr 2 intercalation on T c tried discussion from the view point of hole doping and interblock coupling effect.