Neutron Diffraction Studies on Ba$_{0.95}$K$_{0.05}$Mn$_{2}$As$_{2}$

There has been a great deal of interest in compounds, such as BaMn$_{2}$As$_{2}$, which are closely related to the iron pnictide superconductors. Although undoped BaMn$_{2}$As$_{2}$ is an antiferromagnetic (AF) insulator[1, 2], recent studies of lightly doped Ba$_{1-x}$K$_{x}$Mn$_{2}$As$_{2}$ have shown a striking change to metallic behavior for $x \quad >$ 0.01 and, therefore, may offer a bridge between the high $T_{c}$ cuprates and the iron-pnictide superconductors. We will present neutron diffraction measurements on polycrystalline Ba$_{0.95}$K$_{0.05}$Mn$_{2}$As$_{2}$ performed on the powder diffractometer at the Missouri Research Reactor. Our measurements reveal that the antiferromagnetism in the doped compound remains nearly the same as that found for undoped BaMn$_{2}$As$_{2}$, characterized by a G-type collinear AF spin structure below $T_{N }\sim $ 607(2) K with an ordered moment of 4.21(6) $\mu _{B}$/Mn ion at 14 K. Research at Ames Lab was supported by the USDOE, Basic Energy Sciences under Contract No. DE-AC02-07CH11358. \\[4pt] [1] Y. Singh et al., Phys. Rev. B \textbf{80}, 100403 (2009). \\[0pt] [2] D. C. Johnston et al., Phys. Rev. B \textbf{84}, 094445 (2011).