Effects of Interfacial Interactions on Magnetic Properties in Magnetic Multilayers and Nanostructures

Abstract

In depth understanding of interfacial interactions in ferromagnetic thin film multilayers and nanostructures is of fundamental importance in condensed matter physics as well as in the application of spintronic devices. In Heavy Metal/Ferromagnet systems, due to the intrinsic symmetry breaking at interfaces and large spin-orbit coupling leads to Interfacial Dzyaloshinskii-Moriya Interaction (IDMI), a crucial ingredient for next-generation memory and logic gate devices. Additionally, various interfacial modifications predominantly affect the magnetic characteristics and magnetization reversal mechanisms. This thesis investigates the effects of interfacial interactions on magnetic properties in magnetic multilayers and nanostructures both experimentally and by means of micromagnetic simulation. We present a thorough study of structural and magnetic properties in technologically important Ta/CoFeB/TaOx heterostructures and Ta/CoFeB multilayered thin film stacks with various Ta layer thicknesses. One set of the sputter deposited samples is annealed up to 300 and#730;C, possibly modifying the interfaces. Primarily the magnetic properties have been studied by using a Vibrating Sample Magnetometry (VSM) and Magneto-Optical Kerr Effect setup (MOKE). The results reveal a tunable magnetic anisotropy and an enhancement in saturation magnetization (Ms) values in multilayered stacks by suitably changing the thickness of the intermediate Ta layer and annealing the stacks newline