The effect of Cu/Mn substitution in 2223 Bi-based HTSC

Abstract

The effect of partial Cu by Mn substitution in the 2223 high-Tc superconductor (Bi0.8Pb0.2)2(Sr0.9Ba0.1)2Ca2(Cu1−xMnx)3O10+y with Mn concentration in the range 0<x<0.3 was studied by resistivity, DC susceptibility, XRD, EDX, and neutron diffraction measurements. The EDX analysis confirmed the Mn presence inside the grains in Mn-doped samples. Neutron diffraction measurements show no evidence for magnetic ordering of Mn for 20K<T<300K. The critical temperature, Tconset, of the samples, determined from the temperature dependence of the electrical resistivity, R(T), and from the diamagnetic response, M(T), show no changes of Tconset=108K for a wide Mn concentration range, 0<x<0.2. A substitution of Cu by Mn in the Cu–O pyramids and not in the Cu–O sheets of the 2223 lattice may be the reason of the Mn concentration independence of Tconset.