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

We report measurements of the temperature dependence of the electrical resistivity, ρ(T), and magnetic pen-etration depth, λ(T), for polycrystalline samples of Eu0.5K0.5Fe2As2 with Tc = 31 K. ρ(T) follows a linear temperature dependence above Tc 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.