Structural ordering and chemical configuration of Ba-based infinite-layer superlattices

In this work, we present a detailed structural and microanalytical study of ${\mathrm{BaCuO}}_{\mathrm{2}}{\mathrm{/CaCuO}}_{\mathrm{2}}$ superlattices grown on (001) ${\mathrm{SrTiO}}_{\mathrm{3}}$ substrates by pulsed laser deposition technique. Our analyses were performed by using high-resolution x-ray diffraction, reciprocal space mapping, x-ray specular reflectivity, and x-ray photoelectron spectroscopy. We found that the ${\mathrm{BaCuO}}_{\mathrm{2}}{\mathrm{/CaCuO}}_{\mathrm{2}}$ superlattices are grown pseudomorphically on the ${\mathrm{SrTiO}}_{\mathrm{3}}$ substrate. X-ray photoelectron spectroscopy measurements show that the Ca is partially oxidized having both Ca–O and Ca–Ca bonds, while Ba is completely oxidized (Ba–O bonds). The results of our analyses demonstrate that the pulsed laser deposition technique allows one to fabricate high quality infinite-layer superlattices of high structural and chemical ordering.