Spatially inhomogeneous ultrafast demagnetization of a nickel magnetoplasmonic crystal

A 50% decrease in the magneto-optical Kerr effect is observed in the experiment on subpicosecond laser-induced demagnetization of the one-dimensional all-nickel magnetoplasmonic crystal. The femtosecond pulse energy density is comparable to that required to achieve similar values in thin films. Numerical calculations show that such a decrease is not governed by the uniform reduction of surface magnetization, but is the result of the appearance of demagnetized and non-demagnetized areas of the surface.