Structural properties and Raman spectroscopy of La(2+4x)/3Sr(1−4x)/3Mn1−xCuxO3(0⩽x⩽0.2)(0⩽x⩽0.2)

We present the results of the Rietveld refinement of X-ray powder diffraction and Raman spectroscopy of samples La(2+4x)/3Sr(1−4x)/3Mn1−xCuxO3(0⩽x⩽0.2)(0⩽x⩽0.2) with the Mn3+/Mn4+ ratio fixed at 2:1. By comparing with the Raman spectra of the single doping samples La2/3Sr1/3Mn1−xCuxO3, we found, for the same Mn3+/Mn4+ ratio these spectra start exhibiting some new features following with the increasing concentration of Cu substitutions. Moreover, we also have observed that the A1g mode is substantially shifted with increasing Cu substitution. The A1g phonon mode depends linearly on the A-site mismatch factor σ2σ2, which is influenced mainly by the variety of the 〈rA〉〈rA〉.