Highly conductive metal-topped magnetic multilayers serve as a robust platform for enhancing surface functionalities, such as electrical conductivity, catalytic properties, and biocompatibility in thin film technology. The addition of metal coatings, particularly gold, improves film stability, corrosion resistance, microstructure refinement, and surface conductivity. Gold-coated magnetic multilayers are especially beneficial in applications requiring superior surface conductivity and bio-friendly interfaces. Moreover, they are instrumental in X-ray and neutron reflectometry studies of sharp interfaces and membranes, where the signal-to-noise ratio is typically low. The Zeeman contrast, enhanced by well-defined polarization of incoming neutron beams, can further optimize these conditions. Additionally, gold’s non-toxic and biocompatible nature makes it ideal for supporting biological membranes.

In this study, CoFe₂O₄ thin films were fabricated on Si(100) substrates and annealed both before and after gold coating. The surface texture and magnetic coercivity of the gold-coated, annealed CoFe₂O₄ films exhibited significant improvements compared to previously reported CoFe₂O₄ thin films deposited on gold nano islands [S. E. Shirsath et al., 2019]. A systematic theoretical investigation comparing the influence of gold layers beneath versus on top of the CoFe₂O₄ layers revealed that the Co-ferrite exhibited a dominant texture along the (111) plane, while annealed CoFe₂O₄ showed a dominant texture along the (311) plane. Upon annealing, the initially conformal gold film transformed into a network of micro-islands at elevated temperatures.

Raman analysis of the as-sputtered, annealed, gold-coated, and annealed-then-gold-coated films demonstrated the suppression of the 693 cm⁻¹ tetrahedral Fe-O bond vibration. This suppression is attributed to the influence of the heavier Au atoms rather than the Co atoms. These experimental results are further supported by phonon analysis using density functional theory