The Impact of Fe2+ and Fe3+ Segregation on the Structural and Magnetic Properties of ZnO/Fe Multilayers Deposited via Sputtering: A Study Using EELS and EDS

Ferromagnetic (FM)-metal/oxide multilayers play a central role in achieving highly efficient spin injection, crucial for determining the performance of spintronic devices. In this study, we investigate the microstructural and magnetic properties of [ZnO(5nm)/Fe(t)]
6
multilayers (t = 0.3, 0.4, 0.6, 0.8, and 1.0 nm) deposited on SiO
2
/Si substrates using magnetron sputtering. Characterization of the multilayers was conducted through transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). XRD, XRR, and TEM analyses reveal the presence of multiple crystallographic defects and macroscopic periodicity. Consistent chemical profiles across the ZnO/Fe multilayers were identified through EELS and EDS methods. The saturation magnetization of the multilayer with t = 0.3 nm is approximately five times lower than that of the multilayer with t = 1 nm, and this discrepancy is attributed to indirect coupling between isolated Fe ions rather than the presence of clusters. These findings contribute to a comprehensive understanding of the microstructure and magnetic properties of the investigated ZnO/Fe multilayers, offering insights for their potential applications in spintronics.