Lanthanum-strontium manganites for magnetic nanohyperthermia: Fine tuning of parameters by substitutions in lanthanum sublattice

Ln-doped La 0.7− x Ln x Sr 0.3 MnO 3 (Ln – Nd and Sm) nanoparticles were synthesized via sol-gel method with further heat treatment at 800 °C. Crystallographic, magnetic and calorimetric properties of the obtained nanoparticles have been studied. According to X-ray data, all particles have crystalline perovskite structure and lattice cell volume decreases with growing Ln content. It follows from magnetostatic measurements that the increase in Ln content results in lowering Curie temperature and reduction of room-temperature magnetization. Calorimetric studies show that the action of an external alternating magnetic field causes the effective heating of nanoparticles at temperatures lower than Curie temperature, while heating efficiency strongly weakens upon a transition into paramagnetic state. Thus, fine tuning of the Curie temperature of nanoparticles allows controlling the maximal temperature achieved during the heating, which is important for application of these materials as mediators of self-controlled magnetic nanohyperthermia.