Three-dimensional magnetization evolution and the role of anisotropies in thin Fe/MgO films: Static and dynamic measurements

Abstract

We have quantitatively characterized the real-space components of the magnetization vector M in thin epitaxial Fe(001)/MgO(001) films through an experimental set-up based on the magneto-optical Kerr effect. The capabilities of the method permit to investigate the magnetization reversal under the effect of an applied field directly on the real-space trajectories of M, providing a straightforward interpretation of the magnetization switching mechanisms in terms of magnetic anisotropies and domains formation. Using the pump-probe technique we also studied the three-dimensional precession dynamics of the magnetization vector triggered by a femtosecond laser pulse, revealing how the anisotropy fields (magnetocrystalline and shape) affect the observed features of the precessional dynamics, i.e., the frequency and the amplitude of motion. Our quantitative approach permits a deeper understanding of the basic mechanisms underlying spin dynamics and it can be successfully applied to a large class of magnetic thin layers.