Structural and magnetic properties of Y(Mn1−xFex)12

Abstract

The crystallographic and the magnetic structures of Y(Mn_1−xFe_x)₁₂ intermetallic compounds were investigated. They crystallize in the ThMn₁₂ structure type. The Y atoms occupy the 2(a) sites and the transition metals are distributed on 3 nonequivalent sites 8i, 8j, and 8f. We have determined the solid solubility limit (x = 0.67) of Fe in YMn₁₂. Neutron diffraction spectra at different temperatures have been used to study the nuclear and magnetic structure of Y(Mn_0.7Fe_0.3)₁₂ and Y(Mn_0.4Fe_0.6)₁₂. The Mn and Fe atoms are found to exhibit strong site preference with the i site favoring Mn atoms and the f site Fe atoms. Accordingly the instability of the RFe₁₂ phase can be explained on the basis of the preferential atomic ordering observed in the ternary compounds. Based on the results of magnetic structure refinements using the Rietveld profiling method, antiferromagnetic, noncollinear structures are proposed for these two compounds.