Speaker
Description
Nanocrystalline CuxMn1-xFe2O4 (0 ≤ x ≤ 0.8) ferrites with particle sizes in the range of approximately 8-22 nm were synthesized via a low-temperature glycol-thermal route and systematically investigated for their structural and magnetic properties. X-ray diffraction confirmed the formation of a single-phase cubic spinel structure. The lattice parameter decreased monotonically from 8.506 Å to 8.343 Å with increasing Cu content, consistent with Vegard’s law and the substitution of larger Mn²⁺ ions by smaller Cu²⁺ ions. The increase in X-ray density with Cu concentration reflects enhanced atomic packing within the unit cell. Detailed magnetic studies were performed on the impurity-free composition Cu0.3Mn0.7Fe2O4 as a function of measuring temperature. S-shaped magnetization curves with near-zero coercivity at room temperature indicate superparamagnetic behaviour. The saturation magnetization decreased from ~75 emu g⁻¹ at 10 K to ~48 emu g⁻¹ at 400 K due to thermal spin disorder. The enhancement of coercivity at low temperatures is attributed to surface spin-freezing effects. Zero-field-cooled and field-cooled magnetization measurements yielded a blocking temperature of ~120 K, confirming superparamagnetic relaxation with spin-glass-like behaviour at low temperatures.
| Apply for student award at which level: | PhD |
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| Consent on use of personal information: Abstract Submission | Yes, I ACCEPT |