R V Upadhyay
Articles written in Pramana – Journal of Physics
Volume 63 Issue 2 August 2004 pp 285-290
Small-angle neutron scattering studies have been carried out to check the structural integrity of citryltrimethylammonium bromide (CTABr) micelles in a magnetic fluid for different magnetic fluid concentrations at two different temperatures 303 and 333 K. It is found that the CTABr micelles grow with increasing magnetic fluid concentration and there is a decrease in the micellar size with increase in temperature.
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 77 Issue 2 August 2011 pp 345-355
Magnetic ﬁeld-induced dispersion of ultrasonic velocity in a Mn0.7Zn0.3Fe2O4 ﬂuid (applied magnetic ﬁeld is perpendicular to the ultrasonic propagation vector) is determined by employing continuous wave method. The magnitude of dispersion initially decreases with increasing ﬁeld, then increases and reaches a plateau at higher ﬁelds. Results indicate that the velocity anisotropy is dominated by grain–grain interactions rather than grain–ﬁeld interaction. At the critical temperature, the grain–grain interaction becomes weak as the transverse component of the particle/cluster moment is larger than the longitudinal one and the system reaches saturation even at low ﬁeld. These observed variations in the ﬁeld-induced anisotropy are analysed by incorporating the moment distribution of particles in Tarapov’s theory (
Volume 94, 2020
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