Spinel CoFe2O4/NiFe2O4 bilayer thin films with enhanced resistive switching and magnetic modulation

Designing multilayer resistive switching (RS) structure is an effective strategy to enhance resistive random-access memory performance. However, studies employing bilayer spinel oxides remain limited. In this work, CoFe2O4/NiFe2O4 bilayer thin films were fabricated via sol-gel spin-coating to enhance their resistive and magnetic modulation behaviors. Compared with single-layer devices, the bilayer devices show superior RS performance, including improved voltage uniformity, stable endurance, and reliable data retention, which is largely insensitive to the deposition sequence. As a result of the bilayer structural design, the devices demonstrate markedly enhanced switching behavior, attributed to the rupture of oxygen vacancy-type conductive filaments being confined to the interface of the bilayer film. Besides RS, the bilayer films exhibit magnetic anisotropy and their saturation magnetization is enhanced owing to an increase in oxygen vacancies. The results offer valuable insights into bilayer engineering in spinel oxides, with potential applications in non-volatile memory and multifunctional magnetoelectric devices.