Sp. Taneja et al., MAGNETIC HYPERFINE STUDIES OF NEODYMIUM IRON-OXIDES, Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms, 76(1-4), 1993, pp. 127-129
The temperature dependence of the magnetic hyperfine field of neodymiu
m-iron mixed oxides has been studied by Fe-57 Mossbauer spectroscopy.
Mixed oxides of Nd and Fe in atomic ratios of 1 : 3, 1 : 2, 1 : 1, 2 :
1 and 3 : 1 were annealed at 850, 1000 and 1250-degrees-C. Mossbauer
spectra were recorded between 4.2 and 300 K. For a sample of 1 : 1 com
position (1000-degrees-C annealed) Mossbauer spectra were also recorde
d at high temperatures leading to T(N) congruent-to 660 K. The variati
on of internal magnetic field with temperature (1 : 1 composition, 100
0-degrees-C) closely matches with that of NdFeO3 (perovskite) phase. A
ll samples of 1 : 1 composition show single six-line spectra, indicati
ng one crystallographic site of iron ion. For iron-rich samples, the M
ossbauer spectra showed two sextets which correspond to NdFeO3 and alp
ha-Fe2O3 phases. These results agree with our X-ray and magnetic susce
ptibility studies.