Crystal structure, X-ray emission properties and ⁵⁷ Fe Mössbauer spectra of TaFeP

Abstract The crystal structure of the phosphide Ta 0.88(1) Fe 1.12(1) P has been determined from X-ray powder diffraction data: full-profile refinement, orthorhombic space group Pnma , a = 6.1036(2) Å, b = 3.5774(1) Å, c = 6.9742(2) Å, R I = 0.042. Examination of the X-ray emission spectra (XES) has revealed that the main maximum of the FeLα band coincides with the high-energy feature of the P L II,III bands, indicating strong hybridization of P s and Fe d electrons. High intensity of the FeKβ″ satellite has been observed and explained. Two components appear in the 57 Fe Mössbauer spectruma measured at temperatures in the range 80–300 K, Fe1 (77(2)%) and Fe2 (23(2)%). The paramagnetic component reflects Fe in the crystallographic position 4 c . The moderate value of the quadrupole splitting of 0.3758 mm s −1 indicates a slight anisotropy of the electric field created by Fe1 in its nearest environment. The second component (Fe2) is attributed to Fe atoms statistically substituting Ta atoms in the crystal structure. Its broader linewidth and distinct isomer shift support this assignment. The relative intensities and hyperfine parameters remain constant with temperature, indicating two thermally stable Fe environments. Results of ab initio calculations carried out using the fully relativistic spin-polarized linear muffin-tin orbital method show good agreement with the experimental data.