Manipulation Of Spin-related Properties In Co-based Single-crystalline Heterostructures

Spin-related transport properties are critical performance metrics for spintronic devices,among which perpendicular magnetic anisotropy offers promising potential for increasing the storage density of spintronic devices.In this thesis,we focus on studying the influence of the crystalline structure and the heterostructure interface on the interfacial Dzyaloshinskii-Moriya interaction,the exchange bias effect,and the anomalous Hall effect with Co-based heterostructures that exhibit perpendicular magnetic anisotropy.Primary contents and results are summarized as follows:(1)A non-monotonic dependence of the interfacial Dzyaloshinskii-Moriya interaction on the thickness of Fe insertion was investigated by the combination of experiments and first-principles calculations.It was clarified that as the thickness of the Fe layer decreases from 2 ML to 1 ML,the crystalline structure of the Fe insertion changes from an fcc atomic arrangement to a layer-shift configuration,resulting in an opposite directional iDMI at Fe/Ir interfaces.(2)A significant exchange bias effect was detected in Pt/Co/IrMn3 multilayer with 2-nm thick IrMn3 layer,accompanied by a global uncompensated magnetism in the IrMn3 layer.The atomistic simulations were conducted to investigate the variation of the magnetic structure under lattice stress,indicating that the anisotropic exchange interaction of Mn atoms induced by lattice stress was the dominant origin of the global uncompensated magnetism.Additionally,the lattice strain-induced magnetocrystalline anisotropy resulted in an exchange bias effect in the multilayer with an ultra-thin IrMn layer.(3)An enhancement of anomalous Hall effect in Pt/Co/Pt trilayers was detected by inserting a 2-ML Cr insertion between the MgO substrate and the bottom Pt layer.A specific 90° twinned structure of Pt and Co layers was successfully constructed.By fitting with the proper scaling of the anomalous Hall effect,it was found that the remarkable enhancement of the anomalous Hall effect is attributed to the enhanced phonon skew scattering at the grain boundaries of the twinned traces.