Raman spectroscopy in Zinc Ferrites Nanoparticles

Abstract

ZnFe 2 O 4 ferrite nanoparticles are arousing a great interest in the biomedical field, thanks to their superparamagnetic behavior at room temperature. Functional properties depend on composition, size, nanoparticle architecture and, in turn, on the synthesis methods. Bulk ZnFe 2 O 4 has the normal spinel structure (all Zn 2+ ions in tetrahedral and all Fe 3+ ions in octahedral positions), but at the nanometric size inversion takes place with a cationic mixing on divalent and trivalent sites. The sensitivity of the Raman probe to cation disorder favored the appearance of several works on a rich variety of nanosized zinc ferrites. An overview on these results is reported and discussed at variance with synthesis methods, grain dimensions, and dopants. We add to this landscape our results from new nanosized powder samples made by microwave-assisted combustion, with different dopants (Ca, Sr on Zn site and Al, Gd on Fe site). A detailed analysis of A 1g , E g , 3F 2g Raman modes has been performed and Raman band parameters have been derived from bestfitting procedures and carefully compared to literature data. The vibrational results are discussed taking into account the characterization from X-ray powder diffraction raction, SEM-EDS probe, EPR spectroscopy and, of course, the magnetic responses.

Silver Doped Magnesium Ferrite Nanoparticles: Physico-Chemical Characterization and Antibacterial Activity

“…In agreement with the literature and our previous works on ferrites systems [ 27 , 33 , 34 , 35 , 36 ], the Raman structures in the range 600–800 cm −1 were analyzed in order to obtain the inversion degree, i.e., the amount of Fe cations in the tetrahedra replacing Mg. The data have been processed by the best fitting procedure using a sum of Lorenztian curves ( Figure S5 ).…”

“…The inversion causes the appearance of a doubling of the Raman structures in the spectrum, particularly evident for the A 1g mode. The intensities of the modes are related with the inversion degree [ 35 ]. Magnesium ferrites are inverted spinel-type systems and there is accordance to consider the main Raman feature in the range between 600–730 cm −1 as composed by two bands associated to stretching of the tetrahedral cages, one at lower energies (around 660 cm −1 ) due to Fe–O bonds and the second at higher energies (around 710 cm −1 ) due to Mg–O bonds [ 36 ].…”

Efficacy of surface-functionalized Mg1−xCoxFe2O4(0 ≤x≤ 1; Δx= 0.1) for hyperthermia andin vivoMR imaging as a contrast agent

“…We used Raman spectroscopy to further investigate the structure of the nanoparticles by identifying several vibrational modes. 50–53 Fig. 6(a) shows the Raman spectra of Mg 1− x Co x Fe 2 O 4 (0 ≤ x ≤ 1 with Δ x = 0.1) nanoparticles in the range of 190–1000 cm −1 at ambient temperature.…”

“…We saw earlier that Mg 1− x Co x Fe 2 O 4 ferrites have a partially inverse spinel structure, which is associated with the space group ( Fd 3̄ m ). 51,54–57 The vibrational modes associated with this space group are A 1g (R), E g (R), F 1g , 3F 2g (R), 2A 2u , 2E u , 4F 1u (IR), and 2 F 2u . Notation R implies Raman active vibrational modes, IR symbolizes infrared-active vibrational modes, and the rest are silent modes.…”

Investigation of ZnFe2O4 Films Depending on the Complex Agent Ratio

“…Raman spektrumu spinel ferrit malzeme çalışmalarında sıklıkla kullanılmaktadır (Rivero, 2016). Kübik spinel çinko ferritin Raman saçılma pikleri yani birinci dereceden Raman modları genelde 338, 490, 654 ve 1089 cm −1 'de tespit edilen titreşimlerdir (Galinetto, 2018). Ancak, tetrahedral ve oktahedral bölgelerde Zn ve Fe katyonlarının bulunması yani aynı sitedeki bu iki katyonla ilgili titreşimler, iki ayrı birinci dereceden Raman modunu görüntüleyebilir.…”