Articles written in Pramana – Journal of Physics
Volume 71 Issue 5 November 2008 pp 1069-1074 Small Angle Neutron Scattering
A hydrothermal synthesis route is used to synthesize nanomagnetic particles of Co0.3Zn0.7Fe2O4 ferrite ferrofluids with particle diameter ranging from 5.5–9 nm. XRD analysis shows the formation of a single phase spinel structure. EDX results confirm the stoichiometric composition of the cations. Small angle neutron scattering technique is used to determine the size and size distribution of Co0.3Zn0.7Fe2O4 ferrofluid. The sizes thus obtained are in the range of 5.4 to 8.4 nm. These results are in agreement with magnetic measurements.
Volume 73 Issue 4 October 2009 pp 765-780
Mn0.5Zn0.5Fe2O4 ferrite nanoparticles with tunable Curie temperature and saturation magnetization are synthesized using hydrothermal co-precipitation method. Particle size is controlled in the range of 54 to 135 Å by pH and incubation time of the reaction. All the particles exhibit super-paramagnetic behaviour at room temperature. Langevin’s theory incorporating the interparticle interaction was used to fit the virgin curve of particle magnetization. The low-temperature magnetization follows Bloch spin wave theory. Curie temperature derived from magnetic thermogravimetric analysis shows that Curie temperature increases with increasing particle size. Using these particles magnetic fluid is synthesized and magnetic characterization is reported. The monolayer coating of surfactant on particle surface is confirmed using thermogravimetric measurement. The same technique can be extended to study the magnetic phase transition. The Curie temperature derived using this measurement complies with the low-temperature magnetic measurement. The room-temperature and high-temperature magnetization measurements are also studied for magnetic fluid systems. The magnetic parameters derived for fluid are in good agreement with those obtained for the particle system
Volume 95, 2021
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