Effect of Ni Substitution for Cu in 110 K Phase of (Bi, Pb)-Sr-Ca-Cu-O Superconductors

Abstract

The effect of Ni substitution for Cu in the 110 K phase of (Bi, Pb)-Sr-Ca-Cu-O superconductor was investigated. Samples of Bi 1.84 Pb 0.34 Sr 1.91 Ca 2.03 (Cu 1- x Ni x ) 3.06 O y were prepared. The single phase was obtained up to a Ni concentration of x =0.015. The zero-resistance temperature T c decreased monotonically in the region of x ≤0.03 and became 90 K at x =0.03. T c remained constant at 89 K in the region of 0.03< x ≤0.10. Through X-ray photoelectron spectroscopy measurements, the Cu 2p core level was found to shift toward lower binding energy with the increase of x , which shows the Ni substitution for Cu.