Magnetic properties of crystalline SmFe₂-B alloys

In this paper we report the study of boron substituted SmFe₂ compounds belonging to the family of giant magnetostrictive materials RFe ₂(R=Tb, Dy, Sm). The dc magnetization up to fields of 60 kOe and low field ac sucsceptibility has been measured in the temperature range 5-300 K. In SmFe₂, the temperature dependence of magnetization shows two magnetic transitions at 190 K and 80K in the zero field cooled state. The lower temperature transition is suppressed by the addition of even 1at%B as observed from the dc magnetization. The ac susceptibility shows a pronounced maximum close to 80 K in both the parent compound and in 1 at% B substituted one. This transition presumably occurs due to freezing of domain wall motion.