Magnetic properties of ultra-thin NiFe films

The magnetic properties of ultra-thin (< 1000 Å) NiFe soft magnetic films deposited by electroless and by electrolytic methods from aqueous solutions were investigated, with particular attention to the effect of film thickness on easy-axis coercivity. The Fe content of the alloys was in the range of 15 to 55 at%, with a strong compositional gradient through the film thickness below 500 Å. The easy-axis coercivity showed only very small decrease in thickness below 1000 Å for the range of 17 to 20 at% Fe while it showed a linear dependence with thickness for higher Fe content. It also showed a very strong dependence on the iron content in the NiFe alloy films. Easy-axis magnetic annealing and the application of an external magnetic field during deposition decreased easy-axis coercivity.