JOURNAL OF ALLOYS AND COMPOUNDS, cilt.542, ss.241-247, 2012 (SCI-Expanded)
We investigated intra/inter particle interactions in single domain size magnetite (Fe3O4), maghemite (γ-Fe2O3) and hematite (α-Fe2O3) iron oxide particles. The magnetic analyses were done using vibrating sample magnetometer and magnetic resonance measurements that were taken from 5 to 300 K and from 120 to 300 K, respectively. The magnetic resonance analyses were done for the iron oxides, frozen under 5000 G fields in glycerol matrix. By changing the temperature, a change in resonance field lines was observed at each Fe3O4, γ-Fe2O3 and α-Fe2O3 nanoparticles. However, the fits in resonant lines showed that Landé g values (spectroscopic splitting factor) stayed stable with temperature decrease. The thermal sensitivities that were determined from Landé gfactors, revealed three dominant interactions on resonant lines namely; the exchange coupling in between Fe2+, Fe3+ and O− (g1 = 3.01 ± 0.08), Fe3+ centers (1.88 ± 0.03 ? g2 ? 2.02 ± 0.03, depending on iron oxide states) and flip flop of O− ions in between ionic states of Fe2+–O−1 and Fe3+–O−2 (2.35 ± 0.06 ? g3 ? 2.44 ± 0.06, depending on iron oxide states).