Role of Metal-Oxide Buffer Layers on the Characteristics of Sputtered Magnetite Thin Films

Magnetite ($\text{Fe}_{3} \mathrm{O}_{4}$) is an extremely promising material for spintronics, magnetic storage, and sensing applications, attributed to its unique characteristics, such as near-total spin polarization, a high Curie temperature and the Verwey transition at 120 K. The characteristics of $\text{Fe}_{3} \mathrm{O}_{4}$ thin films are significantly affected by substrate interactions and growth conditions. This study comprehensively investigates the influence of metal oxide underlayers on the structural and transport properties of $\text{Fe}_{3} \mathrm{O}_{4}$ thin films, which were deposited via RF-magnetron sputtering at room temperature on $\text{Si}(100) \backslash \text{SiO}_{2}, \text{Si}(100) \backslash \text{SiO}_{2} \backslash 5 \text{nm} \text{MgO}$, and $\text{Si}(100) \backslash \text{SiO}_{2} \backslash 5 \text{nm}$ Ta $\backslash 5 \text{nm}$ MgO substrates. Results indicate that underlayers such MgO and $\text{Ta} \backslash \text{MgO}$ markedly improve crystallinity, reduce defects, and increase electrical and magnetic characteristics in comparison to films deposited directly on $\text{SiO}_{2}$. These findings highlight the important role of underlayer engineering in enhancing $\text{Fe}_{3} \mathrm{O}_{4}$ thin films for advanced technological applications.