Reduction annealing effects on the crystal structure of $T^{\prime}$-type La$_{1.8}$Eu$_{0.2}$CuO$_{4+\alpha-\delta}$

Abstract

We performed neutron powder diffraction measurements on the as-sintered (AS) and oxygen-reduced (OR) La$_{1.8}$Eu$_{0.2}$CuO$_{4+\alpha-\delta}$ (LECO). The structural parameters for oxygens in AS and OR samples refined by the Rietveld analysis are almost identical to those of the reference system, Pr$_{2}$CuO$_{4+\alpha-\delta}$. Thus, the two systems are comparable in terms of the structural changes in oxygens due to the annealing, although superconductivity appears only in LECO.