Cobalt and iron oxides, due to their tunable structural and magnetic properties, are widely studied for electronic and spintronic applications. However, achieving high coercivity and saturation magnetization in ultrathin films remains a challenge. In this work, we report on the atomic layer deposition (ALD) of nanolaminates and mixed cobalt–iron oxide films on silicon and TiN substrates at 300–450 °C. Using supercycle and multistep ALD methods with ferrocene and cobalt acetylacetonate precursors, we synthesized Co3O4–Fe2O3 bilayers and ternary ferrites (Co2FeO4 and CoFe2O4). The structural, morphological, electrical, and magnetic properties were characterized. We observed that thin films (∼7–12 nm) exhibit markedly enhanced breakdown fields and exceptional magnetic coercivity (up to 25 kOe) and saturation magnetization (up to 1000 emu cm−3), especially after annealing. These results demonstrate a viable route to engineer ferrite-based thin films with superior magnetic and dielectric performance at nanoscale thicknesses.
