Anomalous Raman spectra from La2CuO4

Abstract

We show that some published Raman spectra from the superconductors (La2-xSrx)CuO4 and La2NiO4 are incorrect. We believe that these spectra were obtained when the samples were burnt by the focused laser beam and were actually due to La2O3. Similar anomalous results can be obtained when starting with Nd2CuO4 where the spectra come from Nd2O3. A spectrum distinctly different from those of La2O3 or Nd2O3 is obtained from Y2O3. © 1990 The American Physical Society.