Magneto-resistance study of AFe_{2As_{2 (A = Sr, Ba) iron-based compounds

We have investigated the magneto-resistance (MR) from the two main A Fe 2 As 2 compounds (with A = Sr and Ba) and a low energy Ca ion implanted SrFe 2 As 2 crystal up to 8 T. We show that MR from BaFe 2 As 2 and SrFe 2 As 2 single crystals are similar and a quantum linear MR model favoured by some authors is probably not appropriate especially since the MR is not linear. The SrFe 2 As 2 sample with a near surface Ca concentration of 0.8 at.% has a larger MR at low temperatures that is probably due to current transport in the near surface region and in an inhomogeneous normal and superconducting state.