Neutron Diffraction Study of the Ternary Transition Metal Zintl Compound Ca14MnSb11

The magnetic ordering of the tetragonal Ca 14 MnSb 11 compound (space group I 4 1 / acd ) has been determined by high-resolution neutron diffraction on powder samples. Neutron data were obtained at temperatures of 1.4, 10, 95 K, and room temperature. Refinement of the magnetic structure reveals a ferromagnetic ordering of Mn magnetic moments lying in the a – b plane below the T C of 63 K. The low-temperature-ordered magnetic moment on the Mn ion is 3.4(2) μ B at 1.4 K. The results are confirmed by magnetic susceptibility measurements, which show that the easy magnetization direction of the compound is perpendicular to the c -axis and the system orders ferromagnetically at 63 K, in good agreement with neutron diffraction results. A large negative magnetoresistance effect (Δ ρ / ρ ( H )=−34.4%) at the magnetic transition temperature is observed in applied magnetic fields up to 6 T.