Investigations on structural, magnetic and calorimetric properties of Co2FeSi1−xBx (x = 0–0.5) Heusler alloys: Role of boron

The influence of partial substitution of boron on the structural, microstructure, magnetic and calorimetric properties of Co₂FeSi_1−xB_x (x = 0–0.5) alloys was systematically investigated. The x-ray powder diffraction and microstructural analysis confirmed the presence of second phase in the alloys. From calorimetric studies, it was observed that L2₁–B2 ordering temperature remain constant whereas the melting point decreases with increasing boron content and merges with ordering temperature at x = 0.5. The Curie temperature (T_C) for the alloys x ≥ 0.25 has shown a linear increase with boron concentration. The saturation magnetic moment exhibits a linear decrease and confirms the substitutional effect of boron for Si. With increase in boron content, a compositional shift has been observed which may be attributed to the formation of second phase at the grain boundaries.