Adherence problem for carbon films of up to 0.5 mg/cm 2 on vacuum-deposited thick ferromagnetic Gd targets

Abstract

For high precision measurements of magnetic moments and reduced transition probabilities by the combined technique of projectile Coulomb excitation in inverse kinematics and transient magnetic fields sandwich targets of carbon and gadolinium were required. First preparations revealed a lack of adhesion between the Gd film and the vacuum-deposited C layer. Either the adhesion was generally poor or good results could not be reproduced. Now on a 4 mg/cm 2 Gd target 0.5 mg/cm 2 of natC should be deposited. The Gd was deposited on 1–1.6 mg/cm 2 Ta backings and Cu films of 3.5–7 mg/cm 2 were deposited on the reverse side of the Ta backings. The adhesive properties of evaporated carbon on ferromagnetic gadolinium were investigated. For this either substrate cooling or the deposition of a 5 μg/cm 2 Ti film as adhesion agent were applied.