Normal-state electrical resistivity and superconducting magnetic penetration depth in Eu0.5K0.5Fe2As2

TL;DR

This study investigates the electrical resistivity and magnetic penetration depth in Eu0.5K0.5Fe2As2, revealing linear resistivity behavior, a peculiar low-temperature minimum in penetration depth, and potential magnetic ordering effects.

Contribution

First detailed measurements of resistivity and penetration depth in Eu0.5K0.5Fe2As2, highlighting unusual magnetic features and their relation to superconductivity.

Findings

Resistivity follows a linear temperature dependence above Tc.

Magnetic penetration depth shows an unusual minimum around 4 K.

Short-range ordering of Eu3+ moments influences magnetic properties.

Abstract

We report measurements of the temperature dependence of the electrical resistivity, \rho(T), and magnetic penetration depth, \lambda(T), for polycrystalline samples of Eu_0.5K_0.5Fe_2As_2 with Tc=31 K. $\rho(T)$ follows a linear temperature dependence above T_c and bends over to a weaker temperature dependence around 150 K. The magnetic penetration depth, determined by radio frequency technique displays an unusual minimum around 4 K which is associated with short-range ordering of localized Eu3+ moments.