A study of exchange bias effect in Fe₃O₄/MnO core–shell hetero-nanostructures

Spinel ferrite-based core–shell hetero nanostructures have received a lot of attention in a variety of applications including the development of gas sensors, memory devices, biomedicine, photo catalysts, and electrodes. In this work, we reported Fe₃O₄/MnO core–shell hetero-nanostructure using a simple one-step hydrothermal process. The Field emission scanning electron microscope and X-ray photoelectron spectroscopy analysis indicate the morphology and oxidation states of Fe, Mn, and O present in nanomaterial with an average cluster size of ⁓580 nm. The results of the bulk magnetic measurements of the prepared core–shell hetero-nanostructure indicate the ferrimagnetic behavior at low temperatures with a blocking temperature of ~ 64 K. The interfacial coupling of synthesized heterostructure was evaluated by the observation of the exchange bias effect under field-cooled protocols, which was demonstrated by a large shifting in magnetization in favor of the positive/negative applied field axis relative to the zero field-cooled magnetization curve.