Structural and magnetic properties of Co films on highly textured and randomly oriented C_(60) layers

摘要

The structural and magnetic properties of Co/C_(60)/pentacene and Co/C_(60) thin film structures were investigated. Atomic force microscopy and x-ray reflectivity analysis show that the presence or absence of a pentacene buffer layer leads to a highly textured or randomly oriented C_(60) layer, respectively. A Co film deposited on a randomly oriented C_(60) layer penetrates into the C_(60) layer when it is deposited at a slow deposition rate. The Co penetration can be minimized, regardless of the Co deposition rate, by growth on a highly textured and nanostructured C_(60)/pentacene layer. Vibrating sample magnetometry measurements show that the saturation magnetization of Co/C_(60)/pentacene is significantly reduced compared to that of Co/C_(60). On the other hand, the Co penetration does not seem to have an effect on the magnetic properties, suggesting that the structural properties of the Co and C_(60), layer, rather than the Co penetration into the organic C_(60) layer, are critical to the magnetic properties of the Co/C_(60).