Mössbauer spectroscopy of ⁵ ⁷Fe-doped transition metal compounds
Degree GrantorUniversity of Canterbury
Degree NameDoctor of Philosophy
Mössbauer absorption spectra of ⁵⁷Fe doped into polycrystalline samples of MnS₂, MnSe₂ and MnTe₂ are measured as a function of temperature between 5K and 298K. The hyperfine spectra of these samples are of the pure Fe²⁺ state, and are analysed by diagonalizing the combined magnetic dipole and electric quadrupole Hamiltonian matrix of the first excited state of ⁵⁷Fe. The variation of isomer shift with temperature is analysed on the Debye model. Also the temperature dependences of the magnetic hyperfine fields and their directions are interpreted in terms of crystal-field theory and of the known spin directions of the Mn²⁺ host ions. Finally, the variation of antiferromagnetic transition temperature and of the spin direction as a function of iron concentration in MnSe₂ are investigated.