Study of Oxygen Incorporation in PLD MgB2 Films by Rutherford Backscattering Spectroscopy

The Rutherford backscattering (RBS) method has been employed to study the incorporation of oxygen into MgB2 films during their fabrication by pulsed-laser deposition (PLD). A series of MgB2 thin film samples were analyzed, including two films produced in situ on Al2O3-c substrates (with higher Tc and lower Tc) with an on-axis geometry, one film produced in situ with an off-axis geometry, and one film produced ex situ, with a bulk-like Tc. The amount of oxygen detected by RBS, which is stable in the form of MgO, appears to be correlated with the Tc of the films, the higher the Tc the lower the oxygen content. The superconducting properties of the thin films are discussed in the context of the RBS results.