Magnetic properties of pure and surface treated Vanadium

The very high surface pinning present in superconductors strongly hinders the analysis of fission fragment irradiation experiments which produce heavy damage in a surface layer of approximately 10 μm. In order to decrease this pinning effect, different treatments such as coating with a normal metal or oxygen diffusion can be used. In this paper we show that oxygen doping lowers the critical temperature Tcof Vanadium and surface oxidation reduces drastically the irreversibility of magnetization curves. We show that the dependence of Tcon the oxygen concentration combined with the measurement of the oxygen concentration gradient (obeying Fick´s diffusion law) can explain our magnetic permeability data.