Normal-state electrical resistivity and superconducting magnetic penetration depth in Eu$_{0.5}$K$_{0.5}$Fe$_2$As$_2$

We report measurements of the temperature dependence of the electrical resistivity, $\rho(T)$, and magnetic penetration depth, $\lambda(T)$, for polycrystalline samples of Eu$_{0.5}$K$_{0.5}$Fe$_2$As$_2$ with $T_c=31$ 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 Eu$^{3+}$ moments.