High-Field Magnetization Study of R₂Fe₁₇N₂ (R = Ho and Er) Nitrides

The structure and magnetic properties of the nitrided compounds R₂Fe₁₇N₂ (R = Ho and Er) are studied. The type of crystal structure Th₂Ni₁₇ is preserved upon nitrogenation, and the relative unit cell volume ΔV/V increase exceeds 6%. Magnetic studies are performed in fields up to 60 T at 4.2 K on aligned powder samples. Field-induced spin-reorientation (SR) transitions are observed in the M(H) curves of R₂Fe₁₇N₂. Unlike the parent R₂Fe₁₇ compounds, where the magnetization increases in steps as the field grows stronger, ₂Fe₁₇N₂ demonstrate a gradual increase in magnetization. It is indicative of the change of the SR transition from first to the second type. Extrapolation of magnetization curves to the theoretical value of magnetization in the forced ferromagnetic state yields the coefficient of the inter-sublattice R–Fe exchange interaction. The inter-sublattice exchange is found to decrease upon nitrogenation.