Fractal analysis and atomic force microscopy measurements of surface roughness for Hastelloy C276 substrates and amorphous alumina buffer layers in coated conductors

► The surface roughness of four samples were prepared and analyzed by AFM. ► The surfaces of amorphous alumina layers were found to be fractal in nature. ► The surfaces of Hastelloy substrates were not fractal. ► The flatten modification of AFM images was discussed.