Local Structure of Pr, Nd, and Sm Complex Oxides and Their X-ray Absorption Near Edge Structure Spectra

Pr, Nd, and Sm L1-edge and L3-edge X-ray absorption near edge structure (XANES) spectra of their complex oxides were measured to investigate the relationship between the characteristic feature of the spectra and the local structure around the Pr, Nd, and Sm atoms. The pre-edge peak area of the L1-edge and the full width at half-maximum (fwhm) of the white line of the L3-edge XANES spectra are extracted by curve fitting analyses with one Gaussian and one cubic spline function as a background or with one arctangent and one pseudo-Voigt function, respectively. As a result, a clear correlation between the pre-edge peak area and the fwhm is found with another correlation with abstract physical parameters defined by bond angles formed with Pr, Nd, or Sm and two adjacent oxygen atoms, which represent an indicator of disorder of local configuration of the target element. This finding will open a way to estimate an average local structure of lanthanide elements by means of XANES spectroscopy.