Light element analysis in oxycarbonate superconductors using EELS

Elemental analysis in an oxycarbonate superconductor ((Cu,N,C)Sr2CaCu2Oy) i s conducted using transmission electron microscope-electron energy-loss spe ctroscopy with detector-gain correction. The gain correction enables highly sensitive elemental analysis and precise measurement of energy-loss near e dge structures (ELNESs). It is found that carbon is included as a CO3 group , because the carbon K-edge in the oxycarbonate shows the same ELNES observ ed from CaCO3. Nitrogen ELNES is similar to that of Sr(NPO3)(2), so nitroge n is contained as a NO3 group. Although both CO32- and NO3- have similar pl anar atomic arrangements, the nitrogen ELNES observed is different from tha t of carbon. EEL spectrum simulation based on DV-X alpha method is used to interpret the difference.