Abstract:
The recently discovered spin reorientation in magnetic heterolayers plays a crucial role in spintronics applications. Both first-principles calculated total energy and fitted experimental data remain difficult to quantitatively evaluate the magnetic anisotropy energy (MAE), especially in magnetic heterostructures with complex interfaces between multilayers. An alternative solution is the so-called spin-orbit torque (SOT) method. In this study, the validity of our DFT-based self-developed JunPy [1,2] package with SOT calculation has been rigorously confirmed in two kinds of perpendicular magnetic anisotropy (PMA) systems, including iron thin films [3], and Fe/MgO/Fe magnetic tunnel junction [4]. Our results agree with the conventional MAE calculation but provide deeper insights into atomistic spin dynamics of local magnetic moments. Recently, we has succeed in building up a picture to enrich the fundamental knowledge about the IMA-to-PMA transition in ultra-thin Pd/Co magnetic multilayers and Cr-intercalated CrTe2 layered transition metal halides. The layer-resolved SOT is essential to estimate the average surface anisotropy energy for each surface/interface, but not simply to choose a constant interfacial anisotropy as used in conventional experimental analysis. The main advantage of our DFT-based SOT method is to provide the comprehensive physical understanding in angular momentum transfer between spin and orbital, competition between SOT and spin current accumulation, and precise spin torque acting on each local magnetic moment that is crucial for the atomistic spin dynamics especially in magnetic heterostructures.