Temperature effects on properties of Bi(2223) high temperature superconducting tapes

The critical current density J(c) and the n-value have been studied from 40 K to critical temperature for four types of Bi-system 2223 tapes with diffe rent sheaths. The experimental results demonstrate that the change of J(c) can be divided into three parts and the n-value has some decrease with a de crease in temperature. In engineering applications, a proper working temper ature can be selected to satisfy the practical requirement. Furthermore, th e temperature effects on critical stress for Ag-sheath tape was also studie d. The results demonstrate that the critical stress does not change monoton ically with a decrease in temperature. It increases first, then decreases w ith the further decrease in temperature.