Effects of combined substitution of Dy and Mo or Si on the crystal structures and magnetic properties of Nd1−y Dy y Fe11−x TiM x (M = Mo, Si) compounds

Abstract

A series of Nd1−yDyyFe11−xTiMx (M = Mo, Si) alloys have been prepared by arc melting and studied by X-ray diffraction and neutron diffraction. All samples are found to crystallize in the ThMn12-type structure. The lattice parameters a and c and unit cell volume V of Nd0.5Dy0.5Fe11−xTiMox alloys increase linearly with increasing content of Mo (x), while the lattice parameters a and c and unit cell volume V of Nd0.5Dy0.5Fe11−xTiSix alloys decrease linearly with increasing content of Si(x). In NdyDy1−yFe11−xTiMx (M = Mo, Si) compounds, Ti and Mo atoms preferentially occupy the 8i sites and Si atoms preferentially occupy the 8j and 8f sites. Magnetic measurements show that the substitution of Fe by either Mo or Si leads to a decrease in the Curie temperature.