Weak localization and magnetoresistance of island-like thin copper films

We report magnetotransport and weak localization effects in island-like thin copper films. The samples show significant negative magnetoresistance (NMR) when a perpendicular magnetic field (H˔0.25 T) is applied. When the field is parallel to the film, the samples also show NMR for Hǁ2.5 T, below which positive magnetoresistance (PMR) is found. The temperature dependence of the resistivity and NMR in both perpendicular and parallel fields are due to the weak localization effect in the two-dimensional (2D) system. The observation of NMR in the parallel field is in agreement with Altshuler and Aronov's prediction (B. L. Altschuler and A. G. Aronov, Zh. Eksp. Teor. Fiz. Pis'ma Red. 33, 515 (1981)). The PMR observed at low field is analyzed mainly in terms of the spin–orbit scattering, although other mechanisms may also be possible. It is suggested that the island-like geometry can significantly affect the localization and magnetotransport in 2D metallic films.