(the talk was scheduled for Dec. 20, but will now be given on Jan. 24, 2023) In his overview our guest will summarize hisrecent efforts devoted to the development of magnetic nanoparticles based on transition metal compounds for advanced applications. He will show how magnetic properties of nanomaterials depend on (i) the crystal structure and composition, (ii) the size of particles and their aggregation state and (iii) the core-shell structure of composite particles and nanostructuring.