Mössbauer effect studies of Dy[(Fe0.7 Co0.3)1−x Alx]2 intermetallics

Abstract

It was previously found, that the magnetic hyperfine fields at 57Fe nuclei in the Dy(Mn1−xFex)2 and Dy(Fe1−xCox)2 intermetallic series form the two-branches of the Slater–Pauling curve with a maximum hyperfine field observed for the Dy(Fe0.7Co0.3)2 compound. The Al-substitution of the 3d-sublattice of the Dy(Fe0.7Co0.3)2 compound was studied in the present paper. For this purpose the intermetallic series Dy[(Fe0.7Co0.3)1−xAlx]2 was prepared and data of a detailed X-ray analysis are presented (300 K). The crystal structure depends on the Al-content. 57Fe Mössbauer effect measurements on the Dy[(Fe0.7Co0.3)1−xAlx]2 intermetallics were performed (4.2 K) and the hyperfine interaction parameters were obtained from the experimental Mössbauer spectra. It was found that the magnetic hyperfine field observed at 57Fe nuclei forms a new branch of the Slater–Pauling curve. Some determined crystallographic and Mössbauer data are compared to those already known for the other Al-substituted series. An attempt is made to discuss qualitatively the relations between the Al-substitution, the magnetic hyperfine fields and the possible structure of the 3d-band.