Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
Sci Rep. 2013;3:2154. doi: 10.1038/srep02154.
New BaMnPnF (Pn = As, Sb, Bi) are synthesized by stoichiometric reaction of elements with BaF₂. They crystallize in the P4/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 TN. 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.
新型 BaMnPnF（Pn = As、Sb、Bi）是通过元素与 BaF₂的化学计量反应合成的。X 射线晶体学表明，它们在 P4/nmm 空间群中结晶，具有 ZrCuSiAs 型结构。电阻率结果表明，Pn = As、Sb 和 Bi 分别是具有 0.73 eV、0.48 eV 和 0.003 eV（外推值）带隙的半导体。粉末中子衍射表明，对于 Pn = As，在 T(N) = 338(1) K 以下存在 G 型反铁磁有序，而对于 Pn = Sb，在 T(N) = 272(1) K 以下存在反铁磁有序。所有材料的磁化率在 100 K 以上随温度升高而增加。密度泛函计算发现，这些化合物具有较强的面内和较弱的面外交换耦合，这可能导致在 TN 以上出现非居里-外斯行为。在 4 K 下，从中子衍射实验中精修得到 Pn = As 的有序磁矩为 3.65(5) μB/Mn，Pn = Sb 的有序磁矩为 3.66(3) μB/Mn。
