Growth and superconducting properties of Bi2Sr2CaCu2O8+δ single-crystal whiskers using tellurium-doped precursors

Bi 2 Sr 2 CaCu 2 O 8+δ (Bi2212) single-crystal whiskers were grown by annealing sintered Te-doped Bi–Sr–Ca–Cu–O precursors that had not passed through a melt-quenched glassy state, a process that is known well at this time. The optimum nominal composition of precursors is Ca-rich Bi2Sr2Ca2Cu2Te0.5Ox with a Te content of 0.5. The whiskers contain no Te element. The precursors are mainly composed of Bi2212 and (SrCa)3TeO6 (STO) phases. The STO or the element Te acts as a catalyst in enhancing whisker growth. The critical current (Ic) with a multibranched structure of the current–voltage characteristics due to the intrinsic Josephson junctions along the c axis is quite uniform, showing that the whiskers are homogeneous and of good quality.