Electrical and magnetic properties, and FLAPW electronic band structure of magnetostrictive Tb0.27Dy0.73(Fe0.7−xNixCo0.3)2Tb0.27Dy0.73(Fe0.7−xNixCo0.3)2 compounds

• New complete intermetallic series were prepared.
• ρ0, ρf(T) and ρm(T) contributions are separated. θD and TC are determined.
• The 3d bands are characterized by FLAPW electronic structure calculations.
• ρm∞(T) contribution and magnetic moments of transition metal atoms correlate.
• Curie temperatures are described in relation with calculated magnetic moments.

The structural and physical properties of nickel-diluted Tb0.27Dy0.73(Fe0.7−xNixCo0.3)2Tb0.27Dy0.73(Fe0.7−xNixCo0.3)2 intermetallics were studied by X-ray diffraction, four-probe dc electrical measurements and standard strain gauge method. X-ray analysis shows that all samples crystallize in a cubic Laves structure. The lattice parameter decreases linearly with the nickel content. Electrical resistivity was measured in a temperature range of 15–1100 K. The parameters involved in the dependence of resistivity on temperature and composition were determined. Residual, phonon and magnetic resistivity were separated from the electrical resistivity using both the Matthiessen and Bloch-Grüneisen formulas. The compounds’ Curie temperatures, which decrease nonlinearly with x  , were obtained from the magnetic resistivity curves. The maximum values of magnetostriction attained for the Tb0.27Dy0.73(Fe0.6Ni0.1Co0.3)2Tb0.27Dy0.73(Fe0.6Ni0.1Co0.3)2 compound exceed about 851 ppm. Electronic 3d-band structure and magnetic moment calculations were performed using the Full-Potential Linearized Augmented Plane Waves method. The distribution function for the densities of 3d-states was used to characterise the transition metal subbands.