Electron Magnetic Resonance of Magnetic Nanoparticles

Abstract

The reduction of the size of a material to the nanometric scale introduces significant modifications to its magnetic properties compared to the bulk material, opening new perspectives for its applications in different fields. Within this context, the magnetic resonance technique emerges as an essential technique for studying magnetic nanoparticles, as it is very sensitive to changes in anisotropy and exchange interactions, allowing to distinguish magnetic phases at very low concentrations, study the coexistence of different magnetic phases within the same nanoparticle and obtain information on size and shape distribution and thermal fluctuation effects of nanoparticle systems. In this chapter, we introduce the main features of electron magnetic resonance for magnetic materials in the paramagnetic state and magnetically ordered compounds to analyze the ferromagnetic and antiferromagnetic resonance and emphasize the application of this technique in the research of magnetic nanoparticles. We propose several examples of nanoparticle systems, where the use of magnetic resonance spectroscopy is essential to elucidate their main magnetic features.