Spin-orbit scattering effect on electron-electron interactions in disordered metals

We have measured the low-temperature resistivities of a series of bulk crystalline disordered Ti_73-xAl₂₇Sn_x alloys (x ≲ 5) as well as the sheet resistances of a number of thin ferromagnetic Ni films ( ≈ 120 Å thick) sandwiching an ultrathin Ag or Au ( ≲ 5 Å) layer. The level of impurities (concentration of Sn in the former case, and thickness of Ag or Au in the latter case) is progressively increased in order to enhance the spin-orbit scattering in a controllable manner. The influence of the spin-orbit scattering on the electron-electron interaction effects is studied from the temperature dependence of resistivities (sheet resistance) at low temperatures. We find that the electron-electron interaction contribution to the resistivities (sheet resistances) increases slightly with increasing spin-orbit scattering. Our observation is discussed in terms of the current theoretical concept for the electron-electron interactions in disordered metals.