Amorphous RE–Fe–B–Na colloidal nanoparticles: High temperature solution synthesis and magnetic properties

•RE–Fe–B–Na nanoparticles are obtained by high-temperature solution synthesis.•These colloidal nanoparticles are monodisperse and size controlled.•The magnetism dependence and possible magnetic coupling mechanism are studied.

RE–Fe–B–Na (RE = Nd–Er) colloidal nanoparticles are prepared by high-temperature solution synthesis. These nanoparticles are ultra-small monodisperse, air-stable and amorphous, whose particle size and magnetic property are characterized by transmission electron microscope and superconducting quantum interference device. Taking Nd–Fe–B–Na nanoparticle as an example, it is found that the particle size can be controlled in less than 7 nm. Besides, the magnetic properties of RE–Fe–B–Na colloidal nanoparticles can be compared for different rare earth elements. Based on the bulk ferromagnetic coupling, other possible magnetic coupling mechanism is discussed.

Graphical abstractRE–Fe–B–Na (RE = Nd–Er) colloidal nanoparticles by high-temperature solution synthesis are ultra-small monodisperse and air-stable amorphous, whose size and magnetic dependence are studied.Figure optionsDownload full-size imageDownload as PowerPoint slide