Magnetoresistance in two-dimensional magnesium films of various thicknesses

The magnetoresistance of thin magnesium films in the weakly localized regime has been measured at 4.2 K as a function of film thickness. The results are analysed in a new and simple way based on the theory of Hikami et al. [1]. We use only two adjustable parameters, the inelastic relaxation time _i and the spin-orbit scattering time _so. Whereas _so is found to be almost independent of thickness, _i changes significantly. The variation of _i with thickness is discussed in the light of the theories for the enhanced electron-electron interaction, but it does not seem to tie up with any of the existing theories.