Effect of the distribution of anisotropy constants on the magnetic properties of iron oxide nanoparticles

Daniel Clarke, C Marquina, David Lloyd, Gonzalo Vallejo Fernandez

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The distribution of shape anisotropy constants in two colloids of iron oxide
nanoparticles has been measured from the distribution of particle elongations within each system. The results are in good agreement with the values calculated from a temperature decay of remanence measurement. For a fluid with a saturation magnetisation of 420 emu/cc and an average particle elongation of ~1.3, the distribution of energy barriers is controlled by both the distribution of particle sizes and particle elongations. For a fluid with a saturation magnetisation of 320 emu/cc and a wide distribution of particle sizes, the energy barrier to reversal can be assumed to be controlled by the distribution of particle volumes. These results highlight the need to take into account the distribution of anisotropy constants when making predictions of the heating properties of assemblies of magnetic nanoparticles for hyperthermia applications.
Original languageEnglish
Article number169543
Number of pages5
JournalJournal of Magnetism and Magnetic Materials
Early online date31 May 2022
Publication statusPublished - 1 Oct 2022

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