Magnetic and structural characterization of the [Fe1−xCox]1−yNby system in the range 0⩽x⩽1, 0⩽y⩽0.33

Abstract The main magnetic and structural characteristics of the phases present in the [Fe 1− x Co x ] 1− y Nb y ternary system in the range 0⩽ x ⩽1 and 0⩽ y ⩽0.33 were investigated. The phases observed are based on the α-Fe or e-Fe 2 Nb structures, for x up to about 0.75, and on the γ-Co and e-Co 2 Nb structures in the neighborhood of the Co–Nb edge. While a strict dilution of about 0.4 at% Nb in α-(Fe+Co) does not affect significantly its magnetization, a significant solubility of about 4 at% Nb in γ-Co reduces that parameter by about 12%. The evolution of the hyperfine field of α-(Fe+Co) at room temperature has shown that the presence of Nb in that phase keeps the structure in the disordered state. A phase transformation was observed in e containing 21–27 at% Nb, as the phase becomes magnetic above 20 K after filing the material, with increasing B HF as x increases up to 0.75.