Abstract:
57Fe Mössbauer spectroscopy is one of the most powerful tools that used in studying
magnetic properties of materials. This work aims to investigate the magnetic properties of
MgxSrxMnxCo1-3xFe2O4 (x = 0, 0.1, 0.2, 0.3 and 0.33) nanoparticles annealed at 500 ˚C.
The aim extends to study the magnetic properties of BaFe2O4 sample as a function of
different measuring temperatures. The results showed that magnetic hyperfine fields of
the annealed samples were larger compared to as-prepared samples which agrees with
literature. This reflects the effect of particle sizes on relaxation time τ as explained by
Néel theory. The values of isomer shift were in the range of 0.30 to 0.51 mm/s. This
indicates presence of Fe3+ ions in the samples. The line widths decreased in annealed
samples compared to as-prepared ones.
Investigation the magnetic properties of BaFe2O4 sample as a function of different
measuring temperatures of 77, 80, 90, 160, 200, 250 and 300 K revealed that increasing
of measuring temperature changed the ferrimagnetic order of the sample to paramagnetic
state. Isomer shift values were in the range of 0.30 to 0.45 mm/s, which related to Fe3+
ions. Line width values show no significant trends with increasing measuring
temperatures.
The results showed that temperature (annealing or measuring) has significant influence
upon hyperfine parameters therefore; it can decide the magnetic state of a material.
