Improved spin dynamics in soft magnetic films from 2D arrays of stripes and dots patterned by laser ablation

Abstract
Alterntive to photolithography process for fabrication of 2D arrays of magnetic dots is proposed from a very simple, fast and low cost technique, of laser ablation. Magnetic films with different compositions, structures (NiFe, CoZr, FeN monolayers and [Co/Cu]_n multilayers) and thickness (from 100 to 300 nm) have been submitted at the focalisation point of an ionized argon laser (3W CW maximum power) to a lateral movement produced by a motorized X-Y translation stage. Tracks of partial or total ablation down to the substrate can be realized with well defined width from 3 to 100 microns, depending on the laser beam defocusing and power and on the sample velocity. The possibility of different patterns corresponding to stripes, bars and square 2D arrays with dinerent shape factor is described with size decreasing from millimeter to micron scale. It is shown that laser sputtering can induce strong changes in both static and dynamical magnetic properties of the films as discussed from the magnetization processes of domain wall at low frequency and the complex permeability in the microwave range.