Crystal structure, magnetic properties, and Mössbauer spectroscopy of new layered iron oxyselenide Nd2Fe2O3Se2.

The crystal structure and magnetic properties of a new layered iron oxyselenide Nd(2)Fe(2)O(3)Se(2) have been investigated through powder x-ray diffraction, magnetic susceptibility, specific heat, and (57)Fe Mössbauer spectrum measurements, and electronic structure calculations. This oxyselenide crystallizes in a tetragonal structure (space group I4/mmc) which is isostructural with La(2)Fe(2)O(3)Se(2). The lattice parameters were estimated to be a = 4.0263(1) Å and c = 18.4306(2) Å by the Rietveld analysis. Through its magnetic susceptibility, specific heat, and (57)Fe Mössbauer spectrum measurements, a long-range antiferromagnetic transition of the Fe(2+) ions was found at 88 K and the Nd(3+) ions exhibited Curie paramagnetic behavior down to 2 K. Two magnetic structure models for the Fe(2+) ions were suggested from the Mössbauer spectra.