  We have fabricated Fe-B thin film composition spreads in search of possible
superconducting phases following a theoretical prediction by Kolmogorov et
al.^1 Co-sputtering was used to deposit spreads covering a large compositional
region of the Fe-B binary phase diagram. A trace of superconducting phase was
found in the nanocrystalline part of the spread, where the film undergoes a
metal to insulator transition as a function of composition in a region with the
average composition of FeB_2. The resistance drop occurs at 4K, and a
diamagnetic signal has also been detected at the same temperature. The
superconductivity is suppressible in the magnetic field up to 2 Tesla.
