Excimer laser irradiation effects on soft magnetic properties of sputtered iron nitride thin films

Effect of pulse laser irradiation on soft magnetic properties of reactively sputtered iron nitride thin film has been studied. The as-deposited films exhibit large coercivity in the range 54 Oe to 148 Oe. Laser irradiation results in remarkable decrease in the coercivity of the films, the minimum value achieved being 8 Oe. X-ray diffraction measurements evidence structural relaxation in the films, resulting in densification. Surface roughness of the films exhibits only a marginal increase after laser irradiation. The observed decrease in the coercivity may be attributed to the relaxation of some quenched-in stresses associated with structural relaxation in the films. Irradiation as a function of energy density of laser pulse shows that an optimum energy density is required to achieve the best soft magnetic properties, which can vary from sample to sample.