Synthesis, high-resolution crystal structure refinement and magnetic properties of the manganese-rich cementite-type Mn_(1.8)Fe _(1.2)C

摘要

The manganese-rich ternary cementite phase Mn_(1.8)Fe _(1.2)C has been synthesized by a ceramic route in an almost quantitative yield, and the crystal structure refinement on the basis of high-resolution X-ray powder diffraction data using MoK_α1 radiation has been performed. The carbon atom is found in a slightly distorted trigonal prism composed of Mn and Fe atoms, with a rather narrow bond length range from 1.95 to 2.09 ?. The magnetic susceptibility data clearly indicate long-range ordering phenomena, in particular dominant antiferromagnetic interactions, as predicted by density-functional theory.