A study on magnetoresistivity, activation energy, irreversibility and upper critical field of slightly Mn added Bi-2223 superconductor ceramics

Abstract

This study discusses the effect of Mn addition on the superconducting and physical properties in Bi 1.8Pb 0.4Sr 2Mn xCa 2.2Cu 3.0O y bulk superconductors with x = 0, 0.03,0.06,0.15, 0.3, and 0.6 by means of themagne-toresistivity measurements. The magnetoresistivity of the samples prepared using the standard solid-state reaction method was measured for different values of the applied magnetic field strengths. The superconducting and physical properties of the samples such as the zero resistivity transition temperatures (T c), irreversibility fields (μ 0Hi rr), and upper critical fields (μ 0H c2) were deduced from the magnetoresistivity curves. Moreover, thermally activated flux creep model was studied for activation energy (U0) values of the samples. According to the results of the measurements, not only were the T c and U0 values of the samples found to decrease significantly but the μ 0Hi rr and μ 0H c2 values were also observed to reduce with the increase in the Mn addition, indicating that the doping degrades the physical and superconducting properties of the samples. © 2012 Springer Science+Business Media, LLC.