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Sr-hexaferrite/maghemite composite nanoparticles-possible new mediators for magnetic hyperthermia
P Veverka1, E Pollert, K Závěta
1Institute of Physics, ASCR, Cukrovarnická 10, 162 53 Praha 6, Czech Republic.
Abstract:
Composite nanoparticles with variable ratios of M-type Sr-hexaferrite and maghemite phases were prepared via the sol-gel method employing polyvinylalcohol as the stabilizing agent, followed by thermal treatment at 600 °C for 32-190 min. The measurements in static magnetic field revealed considerable variation of the coercivity and remanence depending on the relative content of the highly magnetically anisotropic Sr-hexaferrite phase. Calorimetric heating experiments were carried out on aqueous gel suspensions under an alternating magnetic field of maximum amplitude H(max) = 15.1-68.4 kA m(-1) and frequency ν = 108 kHz. They showed a strong dependence of the heating efficiency on the coercivity and remanence of the composites, with a specific absorption rate (SAR) value ranging from units to tens of W/g(Fe(ferrimagnetic)).
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