Transport, magnetic and superconducting properties of RuSr2RCu2O8 (R= Eu, Gd) doped with Sn

TL;DR

This study investigates how Sn doping affects the magnetic, superconducting, and transport properties of RuSr2RCu2O8 (R= Eu, Gd), revealing increased disorder, hole concentration, and complex magnetoresistive behavior.

Contribution

It provides a comprehensive analysis of Sn doping effects on magnetic ordering, superconductivity, and electron transport in RuSr2RCu2O8 compounds, highlighting the interplay between disorder and charge carrier dynamics.

Findings

Sn doping reduces magnetic ordering temperature T_m.

Superconducting T_c is slightly reduced with increased upper critical field B_c2.

Normal state resistivity and Hall resistivity decrease despite increased scattering.

Abstract

Ru{1-x}Sn{x}Sr2EuCu2O8 and Ru{1-x}Sn{x}Sr2GdCu2O8 have been comprehensively studied by microwave and dc resistivity and magnetoresistivity and by the dc Hall measurements. The magnetic ordering temperature T_m is considerably reduced with increasing Sn content. However, doping with Sn leads to only slight reduction of the superconducting critical temperature T_c accompanied with the increase of the upper critical field B_c2, indicating an increased disorder in the system and a reduced scattering length of the conducting holes in CuO2 layers. In spite of the increased scattering rate, the normal state resistivity and the Hall resistivity are reduced with respect to the pure compound, due to the increased number of itinerant holes in CuO2 layers, which represent the main conductivity channel. Most of the electrons in RuO2 layers are presumably localized, but the observed negative magnetoresistance and the extraordinary Hall effect lead to the conclusion that there exists a small number of itinerant electrons in RuO$_2$ layers that exhibit colossal magnetoresistance.