Mössbauer absorption spectra have been observed for ${\mathrm{Fe}}_2$B from 290 to 1175 °K. A change in the electric quadrupole interaction was observed from 460 to 480 °K and interpreted as a result of the rotation of the easy axis of magnetization as a function of temperature. The effective magnetic hyperfine field as a function of temperature is found to be described by ${(1-\frac{T}{T_C})}^{\beta }$ in the range defined by $1.2\times {10}^{-3\mathrm{}}\le 1-\frac{T}{T_C}\le 7\times {10}^{-1\mathrm{}}$ for $\beta =0.32\mathrm{}\pm 0.01$. A discontinuity in the isomer shift of 0.018 ± 0.010 mm/sec was found across the ferromagnetic transition.

• Received 24 July 1972

DOI:https://doi.org/10.1103/PhysRevB.7.23