Structural and magnetic analysis of Cd-Zn spinel ferrite nanoparticles

Abstract

Sol-gel auto-combustion synthesis technique was employed to synthesize Cd-Zn ferrite nanoparticles with composition Zn1-xCdxFe2O4, where 0.0≤ x≤ 1.0. The physical properties of prepared samples were inspected by using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and vibration sample magnetometer (VSM) techniques. XRD analysis confirmed the formation of Cd-Zn spinel nano-ferrites with an increase in experimental lattice constant from 8.37 Å to 8.74 Å for zinc and cadmium ferrite samples, respectively. Variation of tetrahedral and octahedral hopping lengths, crystallite size, microstrain and dislocation density with Cd-content has been investigated and elucidated. SEM micrographs showed agglomeration of nearly-spherical grains that increased in size with Cd-content increase. FTIR analysis confirmed the existence of the characteristic tetrahedral and octahedral stretching vibrations of metal ion and oxygen complex in the range 429-558 cm-1. VSM measurements revealed a tuning in coercivity to higher values and a decrease in saturation magnetization as Cd-content increased. The calculated cations distribution, bond lengths, bond angles and interionic distances between cations at tetrahedral and octahedral sites attribute the observed decrease in saturation magnetization to weak interaction between cations in the two sites.

Influence of samarium on the structural, magnetic, and gas sensing performance of cadmium zinc ferrites

“…The validity of the N-R plots shown in figure 3 was checked using R 2 values of the linear fits, which are close to unity in all the studied samples. The obtained value of the lattice parameter for the pure Cd 0.5 Zn 0.5 Fe 2 O 4 sample was close to that reported in literature [45,46]. The lattice parameter of the prepared samples with Sm 3+ doping is found to increase with increasing Sm 3+ content except the sample S4 which showed a decrease in a (table 2).…”

“…All samples revealed narrow hysteresis loops that are nearly flat with flatness values ranging from 9.9 to 41.8, where the S-shaped hysteresis appears a little more pronounced in S4 sample with flatness 9.9. Similar flat loops were reported in literature for cadmium-zinc and zinc ferrites [46,47,64,97,98]. The magnetic analysis from figure 16 revealed very low coercivity H C and retentivity M r ranging between 4-17G and 0.6-3.9 memu/g, respectively.…”

“…The increase in porosity is demonstrated by the decrease in the agglomeration of the nanoparticles, where the increase in porosity means that the grains gets farther apart and vice-versa [65]. Similar morphology was reported in literature of cadmium zinc ferrite prepared using sol-gel methods [45,46,66].…”

“…The nanoparticles have uniform distribution and are found to range between 13.58 and 15.24 nm. This is smaller than the grain size reported in literature [45,46,[66][67][68]. The introduction of Sm 3+ contents into cadmium zinc ferrite samples resulted in a trend like that of the crystallite size shown in figure 8.…”

“…The saturation magnetization M S in table 4 shows that decreases with the increase of doping concentration of Sm which can be attributed to the decrease in the grain size. It is also reported in literature [46] that M S decreases with the increase in lattice parameter resulting in the expansion of the unit cell thus increasing the interatomic distance between the tetrahedral and octahedral sites. Hence, the amount of superparamagnetic particles in the ferrite sample increases causing a decrease in M S [100].…”