Crystal structure and magnetic modulation in β- C e2 O2FeS e2

Abstract

We report a combination of x-ray and neutron diffraction studies, Mössbauer spectroscopy, and muon spin relaxation (μ+SR) measurements to probe the structure and magnetic properties of the semiconducting β-Ce2O2FeSe2 oxychalcogenide. We report a structural description in space group Pna21 which is consistent with diffraction data and second harmonic generation measurements and reveal an order-disorder transition on one Fe site at TOD≈330K. Susceptibility measurements, Mössbauer, and μ+SR reveal antiferromagnetic ordering below TN=86K and more complex short range order above this temperature. 12 K neutron diffraction data reveal a modulated magnetic structure with q=0.444bN∗.