Mössbauer effect study of Y(57FeMn)2

YMn₂ compound doped with⁵⁷Fe was investigated using⁵⁷Fe Mössbauer resonance in the temperature range 4.2–400 K. The magnetically split spectra were analyzed assuming two magnetically nonequivalent Fe sites with relative population dependent on iron concentration. In the transition temperature region a coexistence of the magnetic and nonmagnetic components was observed in the temperature span of about 50 K. A thermal hysteresis (of about 25 K) of the magnetic component confirms the first-order type magnetic transition. Temperature dependence of the hyperfine field of the magnetic component could be interpreted in terms of spin-fluctuation theory.