Magnetic and power absorption measurements on iron oxide nanoparticles synthesized by thermal decomposition of Fe(acac)3

• Published in: Journal of magnetism and magnetic materials Vol. 449; pp. 286 - 296
• Main Authors: Jović Orsini, N., Babić-Stojić, B., Spasojević, V., Calatayud, M.P., Cvjetićanin, N., Goya, G.F.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2018
• Subjects: Magnetic hyperthermia; Néel relaxations; Specific absorption rate; Thermal decomposition method; Magnetic hyperthermia; Néel relaxations; Specific absorption rate; Thermal decomposition method
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2017.10.053

[Display omitted] •7–12 nm in size IONPs were synthesized by thermal decomposition of Fe(acac)3.•Heating rate to reflux can be the most important factor which determine size.•The magnetic anisotropy constant is in the range, Keff = (17–41) kJ/m3.•In TOPO-coated 12 nm sized NPs, SAR ∼ H02f2 due to lower magnetic anisotropy.•Our systems dissipate power exclusively through the Néel relaxation processes. Iron oxide magnetic nanoparticles with diameters d, 7 nm ≤ d ≤ 12 nm, were synthesized by thermal decomposition of Fe(acac)3. Different experimental conditions, keeping constant concetration of Fe ions in solvent, showed that the heating rates is the most important parameter determining the final particle size. Use of two different solvents, 1-eicosene and 1-octadecene, yielded similar nanoparticle sizes (7.1 nm ≤ d ≤ 7.5 nm), but different magnetic anisotropies. All samples were superparamagnetic at room temperature. Spin disordering was inferred in samples coated with trioctylphosphine oxide (TOPO) co-ligand in addition to oleic acid and oleyamine. The heating ability of ∼12 nm-sized nanoparticles dispersed in hexane under alternating magnetic fields (3.98 kA/m ≤ H0 ≤ 23.87 kA/m; 229.3 kHz ≤ f ≤ 828 kHz) has been studied, finding a nearly quadratic dependence upon H0, as expected from the linear response theory.