Spin Seebeck effect and large spin conversion in amorphous Fe2TiSb/polycrystalline Y3Fe5O12 thin films

This study investigates spin current generation in a Fe2TiSb/Y3Fe5O12 multi-layer thin film as prepared via the magnetron sputtering method. Comprehensive characterization techniques are employed to assess film properties, including X-ray diffraction, energy-dispersive X-ray spectroscopy, Scanning electron microscopy, and Vibrating sample magnetometer. The Y3Fe5O12 material exhibits a polycrystalline ferromagnetic insulator behavior, while the 20 nm-thick Fe2TiSb film displays small ferromagnetic metal properties with an amorphous structure. Spin current analysis utilizes the longitudinal spin Seebeck effect configuration, considering magnetic field and temperature dependencies and the results show that spin conversion within the Fe2TiSb/Y3Fe5O12 structure is influenced by both the spin Seebeck effect and the anomalous Nernst effect, resulting in an overall spin signal enhancement. The spin Seebeck coefficient of Fe2TiSb/Y3Fe5O12 was approximately 0.103 μV/K within a magnetic field of 300 mT.