Oxide core-shell nanoparticles (CSNPs) have attracted considerable interest for their multifunctional properties. Luminescent ZnO, ferroelectric BaTiO3, and inverse spinel iron oxide can be exploited to develop magneto-luminescent and multiferroic nanomaterials. The novel sonochemical method has been used to synthesize the nanomaterials. Atomic-scale spectroscopy establishes the core-shell nature and multifunctional properties of the nanomaterials. Magnetic hysteresis (coercivity, remnant, and saturation magnetization) and temperature dependent data indicate the key structural difference between the oxidized and reduced ZnO/iron oxide CSNPs. Variation in the coercive field and remnant and saturation magnetization further confirms the presence of different iron oxides in the shell region. Temperature and field dependent magnetization data establish the change in the near superparamagnetic behavior. Modeling of the X-ray photoelectron spectroscopy data and Rietveld refinement of the X-ray diffraction data provide the crystallographic, surface, and interface information. Photoluminescence data prove luminescence of the ZnO core. Transmission and scanning electron microscopy data confirm the multiferroic BaTiO3/iron oxide core-shell nanospheres important for magnetoelectric coupled devices
