Neutron diffraction study of the ternary transition metal zintl compound Ca14MnSb11

摘要

The magnetic ordering of the tetragonal Ca14MnSb11 compound (space group I4(1)/acd) has been determined by high-resolution neutron diffraction on powder samples. Neutron data were obtained at temperatures of 1.4, 10, 95K, 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 63K. The low-temperature-ordered magnetic moment on the Mn ion is 3.4(2) mu(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 (Deltarho/rho(H) = -34.4%) at the magnetic transition temperature is observed in applied magnetic fields up to 6 T. (C) 2002 Elsevier Science (USA). [References: 26]