Optimizing Growth of Yttrium-Iron-Garnet Films for Spintronic Applications

Yttrium Iron Garnet (Y3Fe5O12, YIG) is a ferrimagnetic insulator with a remarkably low Gilbert damping constant (α), making it an ideal candidate for spintronics and magnonics applications. This thesis presents a detailed investigation into the magnetization dynamics of nanoscale thick YIG films deposited on GGG substrates with (100) and (111) orientations. Using radio frequency (rf) magnetron sputtering and oxygen environment annealing, we systematically studied the impact of growth conditions on the Gilbert damping constant.

The structural characteristics of the films were analyzed using X-ray diffraction (XRD) technique, revealing insights into their crystal structure and surface morphology. Static magnetic properties were evaluated with magneto-optic Kerr ellipsometry (MOKE) and vibrating sample magnetometry (VSM), while magnetization dynamics were probed using ferromagnetic resonance (FMR). Through a thorough exploration of film thicknesses and annealing parameters, we achieved significant reductions in the Gilbert damping constant, with the lowest recorded value being α = 2.1 × 10−3.

This research contributes to the fundamental understanding of YIG thin films and highlights their potential for advancing spin-based technologies. The findings underscore the importance of precise control over growth parameters in enhancing the performance of magnetic materials. Furthermore, the thesis outlines future research directions, including the study of the inverse spin Hall effect (ISHE), to further explore the practical implications and potential applications of optimized magnetization dynamics in YIG films.