Scheme of synthesis of NiFe2O4 powders by (a) CSG route, (b) SGC route and (c) the Co-P route.
shows the XRD patterns of NiFe2O4 nanoparticles synthesized by (a) CSG, (b) SGC and (c) Co-P methods.
Table 1
XRD analysis and magnetic characterization results of NiFe2O4 samples.
| Preparation technique | Annealing temperature [°C] | Crystallite size [nm] | X-ray density [g/cc] | Lattice constant [Å] |
|---|---|---|---|---|
| CSG | 1000 | 70.73 | 5.6049 | 8.2215 |
| SGC | 1000 | 26.71 | 4.8974 | 8.3253 |
| Co-P | 1000 | 35.35 | 5.3980 | 8.5998 |
FT-IR spectra of NiFe2O4 nanoparticles synthesized by CSG, SGC and Co-P methods.
Table 2
FT-IR frequency bands of NiFe2O4.
| Synthesis route | IR frequency bands[cm−1] | |
|---|---|---|
| ν1 | ν2 | |
| CSG | 580 | 405 |
| SGC | 592 | 400 |
| Co-P | 586 | 401 |
UV-Vis spectra of NiFe2O4 nanoparticles synthesized by (a) CSG, (b) SGC and (c) Co-P methods.
Table 3
Band gap and crystallite size of NiFe2O4.
| Synthesis route | Band gap [eV] | Crystallite size [nm] |
|---|---|---|
| CSG | 5.9 | 70.73 |
| SGC | 5.2 | 26.71 |
| Co-P | 5.8 | 35.35 |
Hysteresis curves of NiFe2O4 nanoparticles synthesized by (a) CSG, (b) SGC, (c) Co-P methods and (d) normalized M-H loops at ±1500 Oe.
Table 4
Average particle size [nm] of NiFe2O4 nanoparticles determined fromXRD and magnetic properties observed at room temperature by VSM.
| Preparation technique | Crystallite size [nm] | Saturation magnetization MS [emu/g] | Remanence MR [emu/g] | Coercivity HC [Oe] |
|---|---|---|---|---|
| CSG | 70.73 | 36.61 | 8.252 | 72.3 |
| SGC | 26.71 | 3.6691 | 0.857 | 230 |
| Co-P | 35.35 | 28.58 | 11.341 | 201 |
SEM images of NiFe2O4 nanoparticles synthesized by (a) sol-gel, (b) auto-combustion and (c) co-precipitation methods and calcined at 1000 °C.