ELECTRICAL AND MAGNETIC PROPERTIES OF BULK (Bi1.6Pb0.4)(Sr1.8Ba0,2)(Ca1-xErx)2Cu3Oy SUPERCONDUCTING SYSTEM

Abstract

The effects of partial substitution of Ca by Er on the superconductivity and normal state properties of the bulk superconductor ( Bi 1.6 Pb 0.4)( Sr 1.8 Ba 0.2)( Ca 1-x Er x)2 Cu 3 Oy (0≤x≤0.2) have been investigated using electrical resistivity, a.c. and d.c. magnetic susceptibility measurements. Above the excess conductivity region, all samples are characterised by a linear temperature dependence of the electrical resistivity. The analysis of the resistivity data in the normal state reveal that the residual resistivity and the parameter p (related to the percolation path in granular samples) increase with increasing x. The critical transition temperature determined from resistivity data, T c and T c (ρ=0), are identical to intra-and intergrain critical temperatures derived from the a.c. susceptibility measurements. These temperatures decreases linearly with increasing Er content. For samples with x≤0.005 a temperature independent susceptibility was evidenced and for x>0.005 the susceptibility data as a function of temperature is well described by a Curie-Weiss law with an effective magnetic moment corresponding to the Er3+ ion.