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Issue 13, 2012
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New insights into the heating mechanisms and self-regulating abilities of manganite perovskite nanoparticles suitable for magnetic fluid hyperthermia

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Abstract

The heating and self-regulating abilities of La1−xSrxMnO3+Δ ferromagnetic nanoparticles for magnetic fluid hyperthermia are studied. The samples, synthesized by the Glycine Nitrate Process, present non-agglomerated particles but are partially constituted by polycrystalline nanoparticles, displaying average crystallite diameters ranging from 21 to 31 nm. The strontium content of these nanoparticles, between 0.14 and 0.39, is associated with non-stoichiometry effects in the materials, and both govern their Curie temperatures (TC), which range between 13 and 86 °C, respectively. Heating experiments carried out on samples suspended in an aqueous agarose gel and with different alternating magnetic fields derive unexpected maximum temperatures that cannot be explained on the basis of static magnetization data. The measurement of the thermal dependence of the specific absorption rate (SAR) of nanopowders by adiabatic magnetothermia reveals the existence of a dissipation peak just below TC, which is assigned to a Hopkinson peak. This thermal dependence of SAR, together with a simple thermal model that considers a linear approximation for the heat power losses, is crucial to clarify the behavior observed in heating experiments and also to discuss the possibilities of the samples as self-regulating hyperthermia mediators. This analysis emphasizes that, for the correct design of a self-regulating system, the heat power losses determined by the surrounding conditions must be taken into account as well as the heating capacity of the magnetic nanoparticles.

Graphical abstract: New insights into the heating mechanisms and self-regulating abilities of manganite perovskite nanoparticles suitable for magnetic fluid hyperthermia

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Publication details

The article was received on 19 Mar 2012, accepted on 25 Apr 2012 and first published on 27 Apr 2012


Article type: Paper
DOI: 10.1039/C2NR30667K
Nanoscale, 2012,4, 3954-3962

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    New insights into the heating mechanisms and self-regulating abilities of manganite perovskite nanoparticles suitable for magnetic fluid hyperthermia

    E. Natividad, M. Castro, G. Goglio, I. Andreu, R. Epherre, E. Duguet and A. Mediano, Nanoscale, 2012, 4, 3954
    DOI: 10.1039/C2NR30667K

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