Influence of surface and interface modification on the electrical transport behaviors in Co@Cu nanocomposite films

Abstract

The Co@Cu nanocomposite films with different Cu volume fraction (x) were prepared by the plasma-gas-condensation method and their electrical transport behaviors were systematically studied. Our results showed that a small amount of Cu would effectively improve the residual resistivity and saturated anomalous Hall resistivity, while the short-circuiting effect governed the residual resistivity and saturated anomalous Hall resistivity as the x further increased. We constructed the scaling relation between anomalous Hall conductivity and residual longitudinal conductivity at 5 K by changing the x. The results indicated that the scaling relations could be divided into two distinct regions and x = 18.8% was the demarcation point. The universal character of the scaling relation was valid in the range x < 18.8% (scattering dominated); for x > 18.8%, the experimental data obviously diverged from the 1.6 exponent scaling, which might be mainly ascribed to the short-circuiting effect. The experiment provided a distinctive way to study the anomalous Hall effect (AHE) in granular films by altering the composition without changing the grain size.