Clustering of MnFe₂O₄ nanoparticles and the effect of field intensity in the generation of heat for hyperthermia application

Abstract

MnFe 2 O 4 nanoparticles thinly coated with oleic acid were successfully synthesized via a coprecipitation technique. Morphological analysis shows the co-existence of different nanoparticle assemblies such as dense agglomeration, chain clustering, and random clustering, the effect of which was then reflected in the FTIR spectrum and magnetization behavior of the MnFe 2 O 4 nanoparticles. Induction heating study collectively discusses the association of dipolar energy and magnetic anisotropy energy with the applied field intensity in various nanoparticle clustering systems. The highest applied field intensity (H 250 : 14.98 kAm −1 ) at a nanoparticle concentration of 2 mg ml −1 shows a maximum specific absorption rate of 98.37 W g −1 , which is attributed to the effect of threshold field amplitude surpassing the dipolar field energy. The nanoparticle clustering due to an interdigitated effect and chain clustering can effectively contribute to heat generation via Neelian and hysteresis loss mechanism at a suitable high field intensity.

Magnetic hyperthermia application of MnFe2O4 nanostructures processed through solvents with the varying boiling point

“…Additionally, the coercivity Hc is decreasing with the increase in size. This can be supported with single domain particle theory proposed by Stoner and Wohlfarth [41] which shows Hc depends on both the Ms and anisotropy constant (K) given by the equation (3) [42] reported the Ms value of 22 emu g −1 for 15 nm size MnFe 2 O 4 particle by thermal decomposition method. Another study by Pal et al [43] reported MnFe 2 O 4 particle of size 5 nm shows Ms value of 30 emu g −1 .…”

“…The maximum SAR value was obtained by MnF-BE is 438 W g −1 at a concentration of 2 mg ml −1 and with an applied field of 575 Oe compared to other NPs might be due to the cubic shape. This is a high SAR value than the reported literature [42,53]. These results prove that the degree of induced heat by the NPs can be controlled by the concentration and applied field and indicates the suitability of these NPs in magnetic hyperthermia application.…”

A comparative investigation of normal and inverted exchange bias effect for magnetic fluid hyperthermia applications

“…The probable reason for the reduction of SAR value with increase in concentration is due to the dipolar interaction during the spin relaxation process. Generally, dipolar interaction energy imposes a disordering torque which interrupts the Néel relaxation of the magnetic moment through the energy barrier 68 . Interestingly, despite the higher values of saturation magnetization and anisotropy for F, the NPs heating response is more positive or higher SAR is obtained for CS nanocomposites FN and NF, which is due to the magnetic EB or exchange coupling at the interface of the two materials 12 , 26 , 29 .…”

CoFe2O4–Fe3O4bimagnetic heterostructure: a versatile core-shell nanoparticle with magnetically recoverable photocatalytic and self heating properties

“…As can be seen, the SAR value decreases with particle concentration. Probably, the dipolar energy exert a disordering random torque-disrupting spin relaxation process due to competition between the interparticle interaction and interparticle anisotropy and hence SAR value decreases [58].…”