Doping dependence of the gap of cobalt doped BaFe$_{2}$As$_{2}$ from Point Contact Spectroscopy

Point-contact spectroscopy (PCS) is a unique method which has been used for investigating the gap/s of various superconductors including the iron based superconductors. PCS measurements are capable of systematically identifying the size and number of gaps in a superconductor, certain features of various gap symmetries and gap anisotropy. We have performed a-b plane point contact measurements on single crystal Ba(Fe$_{1-x}$Co$_{x)2}$As$_{2}$ samples in the under, optimal, and over-doped cases. Previously we had shown clear evidence of two full gaps in the optimally-doped case. The under and over-doped crystals do not show such definitive evidence of two gaps. The changes in anisotropy and weight of the gaps for these dopings will be presented.