La_1−xSr_xMnO₃ Nanoparticles for Magnetic Hyperthermia

Abstract

Using a modified Heisenberg model and a Green's function technique we have studied the influence of size d and concentration x of Sr dopants on the Curie temperature T C , saturation magnetization M S , coercivity H C and specific absorption rate (SAR) of single-domain La 1Àx Sr x MnO 3 nanoparticles. Their magnetic properties are explained based on the "magnetically death" surface layer and the competition between the ferromagnetic double-exchange and antiferromagnetic super-exchange interaction. We calculated the specific absorption rate which characterizes the efficiency of the absorption energy when the magnetic hyperthermia is applied as a therapeutic method for the treatment of tumors. A set of nanoparticles appropriate for in vivo and in vitro medical applications, such as magnetic hyperthermia and drug delivery to cancer cells, is determined. The established methodology and microscopic model are suitable to study the magnetic properties of low-dimensional systems (thin films and nanoparticles) such as La 1Àx A x MnO 3 with A ¼ Ca, Ag, Ba, Na for medical applications.

(LaCrO3)m/SrCrO3 superlattices as transparent p-type semiconductors with finite magnetization

“…The competition between superexchange and double-exchange (governed by the Goodenough–Kanamori rules 62–64 ), for example, plays a decisive role in La 1− x Sr x MnO 3 (ref. 65) and rare-earth nickelates. 66 Double-exchange is found between Cr 2+ and Cr 3+ ions in LaCrO 3 ceramics 67 and between Cr 3+ and Cr 4+ ions in rutile CrO 2 .…”

Application of Ion‐Doped Y3Fe5O12 Nanoparticles for Self‐Controlled Magnetic Hyperthermia

“…Now we present the numerical calculations for doped YIG NPs with structural formula Y 3 ½Fe 2Ày M y a ðFe 3Àz M z Þ d O 12 , where M ¼ Al, Ga, Sc, In. We first examine the effect of doping for bulk samples to test the model in comparison with the experimental data.…”

“…For the treatment of tumors by SCMH, three groups of compounds have been examined thoroughly: single‐domain magnetites (Fe 3 O 4 or γ‐Fe 3 O 4 ), which have excellent biocompatibility, [ 7 ] iron oxides of structural formula Me 1 −x Zn x Fe 2 O 4 , where Me = Ni, Co, Mn, Zn, Mg, [ 8,9 ] and Sr‐ion doping of manganese perovskites with the structural formula La 1− x Sr x MnO 3 . [ 10,11 ] In our previous studies, [ 8,12 ] we investigated in detail MNPs for the last two groups and determined a set of MNPs, which are suitable for SCMH based on their magnetic phase transitions, size, magnetization, and coercivity values.…”