Magnetic and magneto-optical properties of Fe3O4 nanoparticles modified with Ag

Petrov, D. A.; Ivantsov, R. D.; Zharkova, S. M.; Velikanova, D. A.; Molokeev, M. S.; Lin, C. -R.; Tso, C. -T.; Hsuc, H. -S.; Tseng, Y. -T.; Lin, E. -S.; Edelman, I. S. Source: JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, 493 10.1016/j.jmmm.2019.165692 JAN 1 2020

Effect of Ag inclusions on magnetic properties and magnetic circular dichroism (MCD) of Fe₃O₄ nanoparticles (NPs) in the mixed system of Fe₃O₄ and Ag NPs in dependence on the relative concentration of the components is presented. The samples were synthesized by the thermal decomposition of the mixture of constant concentration of Fe(NO₃)₃·9H₂O and varied concentration of AgNO₃. The synthesized powdered samples consisted of Fe₃O₄ and Ag NPs located very close with each other, and in the most cases the Fe₃O₄ NPs were bordered with the Ag nanocrystals. The Ag introducing in the samples does not effect, practically, in the Fe₃O₄ NPs morphology and size distribution. At the same time, Ag NPs in the powdered samples cause a decrease in the Fe₃O₄ NPs magnetization and shift of the blocking temperature to lower temperatures, both approximately proportional to the Ag concentration. Most significant changes are revealed in the MCD spectra in the energy region of 1.2–2.2 eV. We have discussed the influence of the Ag NPs on the MCD spectra features in terms of the charge-transfer electron transitions.