Micro‐Raman investigation of nanosized zinc ferrite: effect of crystallite size and fluence of irradiation

Abstract

Zinc ferrite nanoparticles of different sizes ranging from 12 to 62 nm were synthesized by using the nitrate route. These nanoparticles were irradiated by a 100 MeV oxygen beam at two fluences: 1 × 10 13 and 5 × 10 13 ions/cm 2 . It was observed that modes corresponding to cubic spinel phase were retained after the irradiation in all the systems. The variation in the parameters of various modes follows phonon confinement, while this effect seems to violate in irradiated specimen. It was found that the irradiation-induced changes in the modes F 2g (2) and F 2g (3) depend on whether the crystallite size of the pristine sample is less than, equal to or greater than the phonon confinement length, while this length is not dominant for the irradiation-induced changes in the mode A 1g . The changes in various parameters of the modes are attributed to the combined effect of the restructuring of the chemical species and ion-induced defects.

Structural and magnetic study of dysprosium substituted cobalt ferrite nanoparticles

“…Bands above 600 cm -1 in the spectra of all nanoparticles, appear due to A 1g symmetry involving symmetric stretching of oxygen atom with respect to metal ion at the tetrahedral site. Low frequency phonon modes, E g and 3F 2g in the spectra correspond to the symmetric and anti-symmetric bending of metal-oxygen bond at octahedral sites [6,[17][18][19]. Thus presence of bands at ~302, 467, 593 and 681 cm -1 reflect E g , F 2g (2), (1) concentration.…”

“…A 1g , 1E g , 3F 2g are Raman active modes in the cubic spinel phase [6,17]. Bands corresponding to these modes generally appear in the range of 200 to 1200 cm -1 [17][18][19].…”

“…Bands corresponding to these modes generally appear in the range of 200 to 1200 cm -1 [17][18][19]. Hence, Raman spectra of Dy 3+ doped cobalt ferrite nanoparticles were recorded in the range of 200 to 1200 cm -1 and are shown in Fig.…”

The effect of annealing on microstructure and cation distribution of NiFe2O4

“…The Raman shift toward lower wave number and the line broadening are generally observed in polycrystalline materials. This effect is attributed to the confinement of optical phonons in a small crystalline particle [32,31].…”

Improvement in Hydrogen Sensing Response of Zinc Oxide Doped with Platinum

“…This peak became broader and less intense with increase in dopant concentration implying the loss in crystallinity whereas the intensity of Raman mode around 581 cm -1 increases in doped samples indicating the increase in defects such as oxygen vacancies with dopant introduction. A shift towards lower frequency values is observed with dopant addition which could be related to reduction in particle size lying in nano-meter regime as explained by phonon confinement model [8,9]. …”