Magnetic and superconducting properties of Y(Ni 1− xMn x) 2B 2C borocarbides

Abstract

Magnetic and superconducting properties of Y(Ni 1− x Mn x ) 2B 2C borocarbide compounds with x=0.0, 0.01, 0.05, 0.10, and 0.15, have been studied by magnetization and electric resistivity measurements. A paramagnetic behavior has been detected for all ( x≠0) Mn impurity concentrations. Total currents were extracted from hystereses loops, following Bean's model. Critical magnetic fields ( H c1) and superconducting transition temperatures were obtained from magnetization and electric resistivity measurements. The fast decreasing of the transition temperatures, even for non-magnetic transition metal impurities, may indicate borocarbides as good candidates to exhibit a non-s-superconducting order parameter. As expected from electronic band structure calculations, superconductivity may be associated to 3d electron pair formation in these compounds. However, in the case of Mn-impurity, the same 3d electrons are also at the origin of the magnetic moment formation.