Lanthanum manganese perovskite nanoparticles as possible in vivo mediators for magnetic hyperthermia

Manganese perovskite La0.75Sr0.25MnO3 nanoparticles of the crystallite size 20–180 nm were prepared starting from citrate gel precursor by annealing in the range of 570–900 °C. It is shown that the decrease of the crystallite size leads to a gradual decrease of the magnetization and Curie temperature. The observed behaviour is a consequence of a non-collinear spin arrangement at the surface layer of crystallites, estimated to be of ∼5 nm. Magnetic heating experiments were carried out with an aqueous stable suspension of a selected sample (M1T=42emu/g, Tc=352K) under an alternating field of Hmax=88mT, ν=108kHz. The yielded values of specific absorption rate (SAR) were found to be larger than 500 W/gMn at 27 °C and 350 W/gMn at 37 °C.