摘要:"The magnetism of magnetic nanoparticles is different from that of the corresponding bulk magnetic material having the same chemical composition. The different magnetic properties of magnetic nanoparticles are mainly due to their small size, in the field of nanometers - tens of nanometers, which lead to a different magnetic structure from the bulk, and the presence of surface effects regarding the noncollinear arrangement of spins that is pronounced. At the same time, at the sizes of magnetic nanoparticles of the order of nanometers, an additional effect appears: superparamagnetism. As a result the magnetization of small nanoparticles is no longer stable, but fluctuating at 180 degrees under the action of thermal activation. This behavior leads to the lack of hysteresis loop in the magnetization of nanoparticles in the external magnetic field and their magnetization is similar to paramagnetics, according to the Langevin function. All these aspects regarding the magnetism of nanoparticles, with multiple applications in nano- and bio-nanotechnology, are presented and discussed in these chapter compared with the magnetism of bulk magnetic material. Also, in the chapter are presented the most important current biomedical applications of magnetic nanoparticles: diagnosis and detection of diseases, smart drug delivery system, therapeutic applications, theranostic applications of multifunctional magnetic nanoparticles"--
