Executive Summary : | Spintronic devices require the creation, propagation, and detection of "pure" spin current with no net charge current for low power consumption. Microwave field excitation of ferrimagnet (FM)/heavy metal (HM) bilayers leads to a nonequilibrium spin potential (accumulation) at the FM/HM interface, resulting in a pure spin current in the HM layer through diffusion. In the spin Seebeck effect (SSE), a temperature gradient induces thermal motion of electrons in the magnetic material, causing a spin imbalance leading to the generation of a spin current. Magnetic insulators (MIs) are the frontrunner in producing pure spin currents via magnonic processes due to their low eddy current losses and negligible anomalous Nernst effects. Epitaxial Y?Fe?O?? (YIG) films with low damping have been extensively exploited, but they require single-crystal garnet substrates and high growth temperatures, making them expensive for integration with existing spintronic technology. Multicomponent spinel Ni?.??Zn?.??Al?.?Fe?.?O? (? ? 5×10-³) and MgAl?.?Fe?.?O? (? ? 1×10-³) layers have been recently explored, but Li and Mn-ferrites are expensive and multiple valency. This proposal proposes the fabrication of epitaxial ZNF/HM (FM/HM) heterostructures for exceptionally high spin current. The project will be divided into three work packages: fabrication of epitaxial ZNF layers with low Gilbert damping constant and reasonably good magnetization values, heavy metal deposition on the top of ZNF using lithography, and measurement of spin current via spin Seebeck effect. |