Electrospinning synthesis of shuttle-shaped NiCuZn ferrites and effect of sintering temperature on their structural and magnetic properties

Combustion Synthesis of Porous NiCuZn Spinel Ferrite Hierarchies and Their Magnetic Properties

“…The diffraction intensity of the NCZF hierarchies shows an “increase‐to‐decrease” trend upon sintering temperature, which reaches the maximum value at 800 °C. This phenomenon can be explained by that the higher temperature may destroy the spinel lattice structure, which is also observed in our previous work [1e,7a] . Furthermore, the lattice parameter of each product was also calculated based on the Rietveld refined XRD results.…”

“…Raman spectroscopy was also conducted to examine the phase evolution upon annealing. As shown in Figure 2b, all the products show typical peaks at 374, 470, 646 and 682 cm −1 , which can be well indexed to the T 2g , E g , (Ni 2+ )A 1g and (Fe 3+ )A 1g bonds in spinel ferrites [1e,7a] . Figure 2c shows the Fourier transform infrared (FTIR) spectrum of NCZF‐1000, where the peaks at 576 cm −1 and 429 cm −1 can be indexed to the metal‐oxygen stretching vibration in tetrahedral and octahedral sites, respectively, confirming the spinel structure [15] .…”

“…The XRD patterns of NCZF‐700/800/900/1000 are shown in Figures 2a and S9, where the peaks at 18.3, 30.1, 35.4, 43.0, 53.4, 56.9 and 62.5° can be well indexed to the (111), (220), (311), (400), (422), (511) and (440) planes of spinel ferrite (JCPDS No. 08‐0234) [1e,13] . The diffraction intensity of the NCZF hierarchies shows an “increase‐to‐decrease” trend upon sintering temperature, which reaches the maximum value at 800 °C.…”

Blowing‐Combustion Synthesis of Sponge‐like NixZn1−xFe2O4 and Its Structural and Magnetic Properties

“…As shown in Figure 2f, the Ni 0.75 Zn 0.25 Fe 2 O 4 is composed of a thin nanosheet with numerous nanoparticles (average size: 158.8 nm, Figure S3) anchoring on its surface. A closer observation (Figure 2g–h) reveals that the substrate nanosheet is amorphous, which is formed by the oxygen loss and evaporation of Zn species at the high temperature, while each nanoparticle is single crystal (Figure 2h) [6b] . The high‐resolution TEM (HRTEM) image taken at the edge of the nanosheet shows an apparent lattice spacing of 0.21 nm, well corresponding to the (400) plane of (Ni, Zn)Fe 2 O 4 (JCPSD No.08‐0234).…”

“…As shown in Figure 1c, the NiFe 2 O 4 shows a typical Raman spectrogram of Fe 2 O 3 , while the characteristic vibration peaks for spinel ferrite can hardly be detected, which suggests the majority phase is hematite Fe 2 O 3 [16] . After increasing the Ni molar ratio, the Ni 0.25 Zn 0.75 Fe 2 O 4 only displays four dominate peaks at 336, 470, 650 and 693 cm −1 , corresponding to the symmetric bending of O to Fe (E g mode), symmetric stretching of Fe (T 2g mode), the Ni 2+ /Zn 2+ ‐O and Fe 3+ ‐O bonds (A 1g ), respectively [6b,17] . Note that the absence of Fe 2 O 3 peaks can be ascribed to its small crystallization and low content in the Ni 0.25 Zn 0.75 Fe 2 O 4 .…”