  Nickel (II) oxide, NiO, a wide band gap Mott insulator characterized by
strong Coulomb repulsion between d-electrons and displaying antiferromagnetic
order at room temperature, has gained attention in recent years as a very
promising candidate for applications in a broad set of areas, including
chemistry and metallurgy to spintronics and energy harvesting. Here, we report
on the synthesis of polycrystalline NiO fabricated using spray-pyrolysis
technique, which is a deposition technique able to produce quite uniform films
of pure and crystalline materials without the need of high vacuum or inert
atmospheres. We then characterized the composition and structure of our NiO
thin films using X-ray diffraction, and atomic force and scanning electron
microscopies, respectively. We completed our study by looking at the phononic
and magnonic properties of our NiO thin films via Raman spectroscopy, and at
the ultrafast electron dynamics by using optical pump probe spectroscopy. We
found that our NiO samples display the same phononic and magnonic dispersion
expected for single crystal NiO at room temperature, and that electron dynamics
in our system is similar to those of previously reported NiO mono- and
poli-crystalline systems synthesized with different techniques. These results
prove that spray-pyrolysis can be used as affordable and large-scale
fabrication technique to synthetize strongly correlated materials for a large
set of applications.
