The magnetic phases of Mn0.90Fe0.10P studied by Mössbauer spectroscopy

Iron/manganese substitution in MnP has been studied by ⁵⁷Mössbauer spectroscopy. The Curie temperature is 250 K, but not all iron nuclei experience a magnetic hyperfine field even at 170 K. The helical structure is developed below 170 K and show modulations of the hyperfine field. The discrepancies from pure magnetic states (ferromagnetic and circular helix) are explained on the basis of the near surroundings of the iron atoms. The differences in the values of the electric monopole and quadrupole interactions at the iron nuclei for FeP and Mn_0.90F_0.10P are interpreted as an effect of lattice expansion.