Comparative study of the third-order nonlinear optical properties of ZnO/Fe3O4 nanocomposites synthesized with or without Ionic Liquid

•The ZnO/Fe3O4 nanocomposites synthesized with IL showed nanoparticles morphology.•The ZnO/Fe3O4 nanocomposites synthesized without IL showed sheet-like morphology.•In sheet-like morphology, Fe3O4 nanoparticles was embedded between ZnO layers.•Both morphology exhibit two-photon absorption (TPA) and self-defocusing nature. The structural and third-order nonlinear optical properties of ZnO/Fe3O4 nanocomposites synthesized with and without ionic liquid (IL) were investigated. The prepared samples are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and vibrating-sample magnetometer (VSM), respectively. The incorporation of Fe3O4 in ZnO was also confirmed by the XRD pattern. Although, according to the literature, SEM images of nanostructures which have been synthesized without IL, illustrated nanoparticle morphology, in the presence of the IL sheet-like morphology has been created in this research. VSM graphs confirmed the sandwich-like formation of ZnO/Fe3O4 nanocomposites in which the Fe3O4 has been embedded between ZnO layers and produced a sandwich-like structure by IL. It led to decrease saturated magnetization of the sheet-like morphology in comparison with nanoparticle morphology. Third-order nonlinear optical properties of ZnO/Fe3O4 nanocomposites have been investigated by the Z-scan technique. The nonlinearity responses of the nanocomposites have been studied during the different incident intensity of the laser. The higher incident intensity led to the higher nonlinearity response of the ZnO/Fe3O4 nanoparticle composites in comparison with ZnO/Fe3O4 sheet-like morphology. Experimental results reveal that the ZnO/Fe3O4 nanocomposites both nanoparticles and sheet-like morphology, exhibit two-photon absorption (TPA) and self-defocusing nature.