Crystal, magnetic, and electronic structures, and properties of new BaMnPnF (Pn = As, Sb, Bi)

摘要

New BaMn Pn F ( Pn = As, Sb, Bi) are synthesized by stoichiometric reaction of elements with BaF₂. They crystallize in the P 4/ nmm space group, with the ZrCuSiAs-type structure, as indicated by X-ray crystallography. Electrical resistivity results indicate that Pn = As, Sb, and Bi are semiconductors with band gaps of 0.73?eV, 0.48?eV and 0.003?eV (extrinsic value), respectively. Powder neutron diffraction reveals a G -type antiferromagnetic order below T_N = 338(1) K for Pn = As, and below T_N = 272(1) K for Pn = Sb. Magnetic susceptibility increases with temperature above 100 K for all the materials. Density functional calculations find semiconducting antiferromagnetic compounds with strong in-plane and weaker out-of-plane exchange coupling that may result in non-Curie Weiss behavior above T_N . The ordered magnetic moments are 3.65(5) μ _B/Mn for Pn = As, and 3.66(3) μ _B/Mn for Pn = Sb at 4 K, as refined from neutron diffraction experiments.