Magnetic structure and Mössbauer study of Fe–Cr-based selenide

Abstract Sample of FeCr2Se4 has been studied with X-ray and neutron diffraction, vibrating sample magnetometer (VSM), and Mossbauer spectroscopy. The crystal structure of FeCr2Se4 has a monoclinic (space group I2/m) phase, with the lattice constants a = 6.26 A , b = 3.61 A , c = 11.82 A , and β = 90.68 ° , respectively. The neutron diffraction patterns were observed from 4 K to room temperature. The magnetic super structure peak disappeared above the Neel temperature. This result is in agreement with the VSM measurements. Temperature dependence of magnetic susceptibility showed an anomalous antiferromagnetic system. The Mossbauer spectra were obtained at various temperatures from 4.2 K to room temperature. Mossbauer spectrum shows a severe line broadening at 4.2 K, and it gives a direct evidence of a large quadrupole interaction in this material, compared to magnetic dipole interaction. The Mossbauer spectrum consists of a doublet at room temperature, denoting a distorted monoclinic symmetry.