Search of new core materials for magnetic fluid hyperthermia: Preliminary chemical and physical issues

Today the use of nanoparticles based on magnetite Fe(3)O(4) or maghemite gamma-Fe(2)O(3) for magnetic fluid hyperthermia (MFH) application is preferred for evident reasons as biocompatibility and easy synthesis. However, they only show moderate heating capacities because their magnetic properties cannot be simply adjusted to a suitable level. A possible improvement of the MFH technique consists in using more complex magnetic oxides such as: (i) cobalt ferrite and derived phases whose magnetic properties depend on the composition and coercivity is essentially controlled by the magnetocrystalline and/or shape anisotropy, (ii) La(1-x)Sr(x)MnO(3) perovskites whose magnetic proper-ties are influenced by the composition and crystallite size, and (iii) SrFe(12)O(19)/gamma-Fe(2)O(3) composites whose magnetic properties are mainly controlled by the ratio of the respective magnetic phases. Our main results concerning the synthesis of these compounds in the form of submicronic particles, their magnetic properties and their heating abilities are summarized, compared and discussed in this paper. (C) 2009 Elsevier Ltd. All rights reserved.