The magnetic and structural properties of melt-spun R8Fe 84Ti8 with R=Nd, Sm, Dy, Gd and R 8(Fe,Co)76[V(Mo)]16 with R=Nd, Sm have been studied with x-ray diffraction, transmission electron microscopy, and magnetic measurements. The tetragonal ThMn1 2-type structure was found in all alloys after annealing at about 700°C. The Curie temperature (Tc) of the as-spun amorphous samples was in the range of 40-100°C. Crystallized Nd8(Fe 1-xCox)84Ti8 samples with the 1:12 structure have a Tc around 250°C for x=0, reaching the value of 660°C for x=0.5 and then decreasing again to 490°C for x=1. ac susceptibility studies on Co-substituted samples showed magnetic transitions in the temperature range 100-200 K. The coercivity was found to be strongly dependent on the microstructure. The highest value of Hc (2 kOe) was obtained in Sm-Fe-Ti samples with a grain size about 500 Å. The upper value of Hc is low because of the presence of some α-Fe in crystallized ribbons.
ASJC Scopus subject areas
- Physics and Astronomy(all)