Sputtered L1₀-FePd and its Synthetic Antiferromagnet on Si/SiO₂ Wafers for Scalable Spintronics

As a promising alternative to the mainstream CoFeB/MgO system with interfacial perpendicular magnetic anisotropy (PMA), L1₀-FePd and its synthetic antiferromagnet (SAF) structure with large crystalline PMA can support spintronic devices with sufficient thermal stability at sub-5 nm sizes. However, the compatibility requirement of preparing L1₀-FePd thin films on Si/SiO₂ wafers is still unmet. In this paper, high-quality L1₀-FePd and its SAF on Si/SiO₂ wafers are prepared by coating the amorphous SiO₂ surface with an MgO(001) seed layer. The prepared L1₀-FePd single layer and SAF stack are highly (001)-textured, showing strong PMA, low damping, and sizeable interlayer exchange coupling, respectively. Systematic characterizations, including advanced X-ray diffraction measurement and atomic resolution-scanning transmission electron microscopy, are conducted to explain the outstanding performance of L1₀-FePd layers. A fully-epitaxial growth that starts from MgO seed layer, induces the (001) texture of L1₀-FePd, and extends through the SAF spacer is observed. This study makes the vision of scalable spintronics more practical.