NiFe2 and its nitride γ-NiFe2N derived from NiFe2O4: Magnetostriction, thermal expansion, resistivity and corrosion resistance

The perovskite γ-NiFe2N with the face centered cubic symmetry, rather than the hexagonal symmetric ɛ-NiFe2N in previous report, was synthesized based on the route from NiFe2O4 to NiFe2 and finally to γ-NiFe2N. γ-NiFe2N presents the enhanced magnetization (a), magnetostriction (b) and resistivity (d); it exhibits the negative thermal expansion in two temperature windows below 60 K and between 235 K and 305 K (c). Furthermore, γ-NiFe2N has the better corrosion resistance in the sodium chloride aqueous solution than NiFe2, as shown in the SEM images (e) and (f). The unique properties and low-cost of γ-NiFe2N may find applications somewhere.