Conductance of atom-sized contacts of transition metals at room temperature

► Room-temperature conductance of Fe, Co, and Ni atom-sized contacts in UHV. ► A conductance peak is found in the histogram of Fe but not in those of Co and Ni. ► The conductance histograms of Ni and Co are featureless but essentially different. ► Our results indirectly prove the proposed contact stabilization in solutions. ► No integer and fractional quantized peaks are observed.