Electrodeposition of Co_xFe_3–xO₄ Epitaxial Films and Superlattices

Spinel ferrites are of interest because of their potential applications in spintronics (spin-based electronics) and solid-state memories. Cobalt ferrite (CoFe 2 O 4 ) is an inverse spinel ferrite. Currently, the utility of CoFe 2 O 4 is mainly based on its high coercivity and magnetocrystalline anisotropy. The magnetic and electrical properties of CoFe 2 O 4 depend on its Co:Fe ratio. In this paper, a one-step electrodeposition of Co x Fe 3-x O 4 (0 < x < 1) thin films from an alkaline Fe 3+ - and Co 2+ -triethanolamine solution is presented. The Co:Fe ratio in the Co x Fe 3– x O 4 thin films can be tuned by controlling the deposition potential. That is, Co x Fe 3– x O 4 thin films with tunable chemical and physical properties can be produced from a single solution. Superlattices in the Co x Fe 3– x O 4 system were also electrodeposited from the same solution by simply pulsing between two potentials. Compared to Co x Fe 3– x O 4 individual films, superlattices exhibit resistance switching and a more pronounced negative differential resistance (NDR) feature at lower current during perpendicular transport measurements, which could be used in resistive random access memories.