Size dependence of plasmon absorption of Ni nanoparticles embedded in BaTiO3/SrTiO3 superlattices

► The nickel nanoparticles with different size were embedded in the barium titanate/strontium titanate superlattices. ► The increasing sizes and irregular shapes of nickel nanoparticles were observed as the increase of laser energy density. ► By the absorption spectra investigation, the absorption peak presented red-shift and broadening phenomenon with the increase of the sizes. ► The results were explained by the calculation of real and imaginary permittivity of bulk nickel.