Anisotropic behaviour of the magnetoresistance in single crystalline iron films

Magnetoresistive properties of single crystalline Fe(0 0 1) films with thic kness in the range 5-100 nm are reported. The films possess low coercive fi elds (similar to 100 A/m) but a weak irreversible behaviour of the magnetiz ation remains to fields of the order of the anisotropy field. The anisotrop ic behaviour of the magnetoresistance is investigated as a function of temp erature and film thickness. A reversal in sign of the anisotropic magnetore sistance from negative to positive values is found at low temperatures on d ecreasing the film thickness from 100 to 5 nm, or by increasing the tempera ture from 10 to 300 K of a sufficiently thick him. The reversal in sign is associated with a crossover from Lorentz force (ordinary) to spin-orbit (ex traordinary) dominated scattering processes governing the anisotropic magne toresistance as the length scale of the electron mean free path, lambda, de creases. (C) 1999 Elsevier Science B.V. All rights reserved.