Synthesis and study of the crystallographic and magnetic structure of DyFeMnO5: A new ferrimagnetic oxide

The title oxide has been obtained by replacing Mn³⁺ by Fe³⁺ in the parent oxide DyMn₂O₅. The crystallographic and magnetic structures have been analysed from neutron powder diffraction (NPD) data, in complement with susceptibility and magnetic measurements. DyFeMnO₅ is orthorhombic, belonging to the Pbam space group as the parent compound. The crystal structure contains infinite chains of edge-sharing Mn⁴⁺O₆ octahedra, interconnected by dimer units of Fe³⁺O₅ square pyramids. There is a certain antisite disorder in the crystal structure, with 8.0% of the Mn⁴⁺ sites occupied by Fe cations, and 8.2% of the Fe³⁺ positions occupied by Mn³⁺ cations. The magnetization measurements show that DyFeMnO₅ presents magnetic order below T_C≈178 K; a study of the magnetic structure from the low-temperature NPD patterns indicates an antiferromagnetic coupling of the Mn⁴⁺ and Fe³⁺ spins, with the polarization of the Dy³⁺ magnetic moments parallel to the those of the Fe sublattice.