Structural Defect Impact on Changing Optical Response and Raising Unpredicted Ferromagnetic Behaviour in (111) Preferentially Oriented Nanocrystalline NiO Films

NiO thin films deposed on a glass substrate, NiO/glass, are successfully prepared using a spray pyrolysis technique (SPT) at 460 degrees C and characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray, Atomic force microscopy (AFM), spectroscopic ellipsometry (SE), Photoluminescence (PL) and diverse electric and magnetic studies. The structural investigation shows that the synthesized films crystallized in a cubic structure with (111) preferential orientation. The NiO layers exhibit a uniform grain of regular sizes with aggregates randomly distributed across their surface. The optical properties of the NiO thin films evidenced a normal optical dispersion as well as good transparency of the NiO films. An unpredicted ferromagnetic aspect was raised due to the high oxygen presence in the synthetized material. A high thermal dependency of the conductivity, as well as a semiconductor behavior of the grown NiO material, is also demonstrated.

Automated summary

NiO thin films were successfully prepared and characterized. The structural investigation revealed a cubic structure with (111) preferential orientation. The NiO layers showed uniform grain size and randomly distributed aggregates. The optical properties exhibited normal dispersion and good transparency. Unexpected ferromagnetic behavior was observed due to high oxygen content, along with high thermal dependency of conductivity and semiconductor behavior.