161Dy and 57Fe Mössbauer effect studies of Dy[(Fe 0.4 Co 0.6) 1− x Mn x] 2 intermetallics

Abstract

It has previously been found that the magnetic hyperfine fields at 161Dy and 57Fe nuclei observed by the Mössbauer effect (4.2 K) in the Dy(Mn 1− x Fe x ) 2 and Dy(Fe 1− x Co x ) 2 intermetallic series treated as functions of the average number of 3d electrons form two different Slater–Pauling curves corresponding to 5d(6s) and 3d bands, respectively. Both curves are composed of a left branch, maximum and right branch.The maximum of the 161Dy curve is shifted to the left by about 0.4 of the 3d electron parameter as compared to the maximum of the 57Fe curve. The starting compound ( x=0) of the studied Dy[(Fe 0.4 Co 0.6) 1− x Mn x ] 2 series belongs to the area of the right branches of the Slater–Pauling curves. In this series, the number of 3d electrons is reduced by the Mn substitution. New compounds were prepared and the X-ray, the 161Dy and 57Fe Mössbauer effect studies were carried out for the series. The 161Dy and 57Fe magnetic hyperfine fields form another two different Slater–Pauling curves. The determined magnetic ordering temperature decreases nonlinearly with the Mn content. Possible relations between the magnetic hyperfine fields and the expected band structure are discussed.