Microstructural and magnetic characterization of Co/CN films fabricated bynanolamination

Nanolamination combined with appropriate annealing treatment has been used to produce high coercivity, heterogeneous Co-CN films with nanostructures r anging from classical granular to an interconnected network. Transmission e lectron microscopy and electron diffraction have been used to quantify the nanostructural evolution and resulting grain size distributions. As-deposit ed nanolaminates with initial layer thicknesses of 1.3 and 2.7 nm are essen tially superparamagnetic. Annealing leads to coercivities of > 1100 Oe. Vis cosity and irreversible susceptibility measurements have been used to calcu late activation volumes of similar to (18 nm)(3), in good agreement with gr ain size analysis. Measurements of the time dependence of coercivity have b een used to calculate the thermal stability factor, KV/kT similar to 480, w hich is independent of initial geometry. Effective first-order uniaxial ani sotropy constants determined using calculated activation volumes are at max imum similar to 75% of the value expected for bulk alpha-Co. This result is consistent with Co present in both alpha and beta phases, as confirmed by electron diffraction. (C) 2000 Elsevier Science B.V. All rights reserved.