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

Magnetite (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Fe}_{3} \mathrm{O}_{4}$</tex>) 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 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Fe}_{3} \mathrm{O}_{4}$</tex> 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 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Fe}_{3} \mathrm{O}_{4}$</tex> thin films, which were deposited via RF-magnetron sputtering at room temperature on <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Si}(100) \backslash \text{SiO}_{2}, \text{Si}(100) \backslash \text{SiO}_{2} \backslash 5 \text{nm} \text{MgO}$</tex>, and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Si}(100) \backslash \text{SiO}_{2} \backslash 5 \text{nm}$</tex> Ta <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\backslash 5 \text{nm}$</tex> MgO substrates. Results indicate that underlayers such MgO and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Ta} \backslash \text{MgO}$</tex> markedly improve crystallinity, reduce defects, and increase electrical and magnetic characteristics in comparison to films deposited directly on <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{SiO}_{2}$</tex>. These findings highlight the important role of underlayer engineering in enhancing <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Fe}_{3} \mathrm{O}_{4}$</tex> thin films for advanced technological applications.