Effect of oxygen alloying on scattering processes in MgB$_{2}$

The effect of oxygen alloying on T$_{c}$, resistivity, H$_{c2}$, and J$_{c}$ of MBE-grown MgB$_{2}$ films was studied. Oxygen was introduced either during growth or by ex-situ heating in oxygen atmosphere. While the concentration of oxygen increased from 1 to 9{\%}, \textit{dH}$_{c2}^{\vert \vert }$\textit{(0)/dT} of the films, at T$_{c}$, increases from 0.67T/K to 1T/K. J$_{c}$s greater than 400 kA/cm$^{2}$( at 8T, 4.2K) have been observed in these films and increased oxygen alloying changes J$_{c}$ very little. $H_{c2}^{\vert \vert }(0)$ and $H_{c2}^{-}$(0) values, obtained in these films with T$_{c}$s $\sim $ 31K, are as high as 43T and 32T respectively. These values are significantly higher than the maximum $H_{c2}^{\vert \vert }(0)$ value obtained for ion irradiated films, neutron irradiated MgB$_{2}$ bulk, and C-alloyed MgB$_{2}$ bulk. ~While the J$_{c}$ values of the oxygen alloyed films are higher than the C-alloyed Penn State films, the H$_{c2}$(0) values are, however, still significantly smaller than the record values found in the C-alloyed films.