Magnetic Properties of Amorphous CoNbZr/AlN Multilayered Films

The dependence of the magnetic properties of multilayer CoNbZr/AlN films on the conditions of film preparation was investigated. AlN films were prepared by N2 reactive sputtering deposition on CoNbZr films. The soft magnetic properties of the as-deposited films were found to be strongly related to the rf input power during AlN deposition. The anisotropy field decreases drastically at an input power of greater than 2 W/cm², and a high permeability of around 10,000 (at 5 MHz) was obtained for as-deposited films prepared at an rf input power during A1N deposition of 4.4 W/cm². SEM observations revealed that CoNbZr films in as-deposited multilayer form have nearly the same morphology as amorphous alloy films annealed at the optimum temperature for reduction of the anisotropy field. The annealing process during film preparation (self-annealing effect) is attributed to the heat generated during AlN deposition, originating mainly in the heat of formation in AlN reactive sputtering.