Study of interfacial engineering on exchange bias effect in NiO/CoFe₂O₄ heterostructures

In the present work, the magnetic properties of NiO/CoFe₂O₄ (CFO) bilayers, grown via pulsed laser deposition on Si (100) substrates, have been investigated. The NiO layer thickness has been varied to explore its effect on the structural, magnetic, and electronic properties of the studied bilayer. Structural characterization of the studied compound has been analyzed using X-ray diffraction, X-ray reflectivity, atomic force microscopy, and Raman spectroscopy. An exchange bias effect has been observed in the studied bilayer, and interestingly, it varies with the thickness of the NiO layer due to the formation of an intermixed layer at the NiO/CFO interface. Furthermore, soft X-ray absorption spectroscopy (SXAS) measurement has also been carried out to study the electronic structure, and the obtained data corroborate well with its structural results. The relationship between the thickness of NiO with exchange bias can be understood through the enhanced interfacial exchange coupling between the CFO and NiO layers.